IT 214 Full Practice Midterm Exam 2
1
1
Project yields
A vertical subset of a table
SQL character data format(s) is(are) ____.
CHAR and VARCHAR
14. Corporations use only structured data.
F
A dependency of one nonprime attribute on another nonprime attribute is a partial dependency.
False
foreign
It becomes difficult to create a suitable ____________________ key when the related table uses a composite primary key.
self join
It is not necessary that a ____ be based on a foreign key and a specified unary relationship
_________ represents a micro view of the entities within the ERD.
Normalization
____ yields a vertical subset of a table.
PROJECT
In-memory databases
Refer to a type of database that stores most of its data in RAM rather than in hard disks.
Unnormalized database tables often lead to various data redundancy disasters in production databases
True
Ternary Relationship
When three entities are associated. Association among 3 different entities
from
a cartesian join may be explicitly created by using the phrase cross join in the ___ statement
INSERT
adds records
A(n) ____ might be written by a programmer or it might be created through a DBMS utility program.
application program
a(n) __ might be written by a programmer or it might be created through a DBMS utility program a. query c. database management system b. operating system d. application program
application program
inner joins
are more common then outer joins
NULLIF and COALESCE
are the keywords associated with the other two forms of the CASE expression
inner join...on
are used to establish an equi-join in the from clause
ORDER BY
been used to organize the order in which the rows of output are listed
A ____ is a collection of related records.
file
Natural
optional keyword when the join is defined in the FROM clause
Lock granularity is
the detail possible with a lock
UNION clause
used to combine the output from multiple queries together into a single result table
Inner Join.. On
used to establish an equi-join in the FROM clause
exists(not exists)
used when your only interest is whether the subquery returns a nonempty(empty) set
Composite Primary Keys
useful for: - composite entities (resolving M:N relationship) - weak entities with strong relationships
Phantom read occurs
when a transaction reads data it has previously read and then finds new rows that were inserted by a committed transaction.
Recursive Relationship
when an entity is related to itself.
Data inconsistency
when different versions of the same data appear in different places.
3NF
when it includes no partial dependencies and it contains no transitive dependencies
data anomaly
when not all of the required changes in the redundant data are made successfully (update anomaly, insertion anomaly, deletion anomaly)
CAST
when performing the union command to merge, use the command to control the data conversion
Concurrent transaction
when two transactions are being processed against a database at the same time.
Full Functional Dependence
when you have all of the attributes you need for the relationship
iN (NOT IN)
when you need to know the values are (are not) in the set
FROM
where the required data is stored from___ keyword
=ALL
which makes sense only when all the elements of the set have the same value
An INNER join
will only return rows from each table that have matching rows in the other.
The EXISTS operator
will return a TRUE value if the subquery resulted in a non-empty set, otherwise it returns a FALSE
NOT EXISTS
will take a value of true if no rows are returned and false if one or more rows are returned
a(n) __ database supports a relatively small number of users (usually fewer than 50) or a specific department within an organization a. desktop c. enterprise b. workgroup d. transactional
workgroup
During the __ phase, changes are permanently applied to the database.
write
MAX
yields the maximum attribute value encountered in given column
SUM
yields the sum of all values given column or expression
The Crow's foot symbol with two parallel lines indicates ____ cardinality.
(1,1)
NoSQL
(Not only SQL) is generally used to describe a new generation of database management systems that is not based on the traditional relational database model
ERD
- Entity Relationship Diagram - Diagram that depicts an entity relationship model's entities, attributes and relations.
To remove a transitive dependency, the designer must
- Place the attributes that create the transitive dependency in a separate table - Make sure that the new table's primary key attribute is the foreign key in the original table.
Weak Entity
- The entity must be existence-dependent on its parent entity. - The entity must inherit at least part of its primary key from its parent entity.
Primary Key Characteristics
- Unique values: must be able to guarantee - Nonintelligent: no embedded semantic meaning - No Change over Time: changing value means changing identity of entity - preferrably single-attribute: minimum # of attributes possible - preferrably numeric: better managed that way - security complaint: not composed of any value that could be a security risk
Inventory has 10 counts.
- User A reduce count of item by 5 - User B reduce count of item by 3
Entity CLUSTER
- a "virtual" entity type used to represent multiple entities and relationships in the ERD. - formed by combining multiple interrelated entities into a single abstract entity object. - used to represent multiple entities and relationships with the purpose of simplifying the ERD and thus enhancing its readability.
Existent-Dependent Entity
- also known as a composite (bridge, join, link, associative) entity - generally used to transform M:N relationships into 1:M relationships.
Constraints
- are important because they help to ensure data integrity. - is a restriction placed on the data.
Cardinality
- assigns a specific value to connectivity. - expresses the of allowed entity occurrences associated with a related entity
Existence-Independent
- entity that can exist apart from one or more related entities. - created first when referencing an existence dependent table to it.
Computer fails for many reasons:
- hardware breaks- electrical power fails- programs have bugs -procedure contain errors- people make mistakes
Entity SUPERtype
- is used to minimize the likelihood of redundant relationships - s a generic entity type that is related to one or more entity subtypes - minimize the number of nulls - contains the common characteristics
Optionality
- means that one entity occurrence does not REQUIRE a corresponding entity occurrence in a particular relationship - has one or more optional relationships - represented by a O
Weak Relationship
- non-identifying relationship - exist when the PK of the related entity does not contain a PK component of the parent entity
DE-Normalization
- process which a table is changed from a higher level normal form to a lower normal form - usually done to increase processing speed - potentially yields data anomalies
Strong Relationship
- requires weak or existent-dependent entities that have primary keys partially or fully made up of the parent entity's primary key. - In a Crow's Foot ERD, a strong relationship is depicted with a solid line connecting the two entities.
Entity SUBtype
- stores data that is UNIQUE TO THE SUBTYPE
Connectivity
- symbols - describes the classification of the relationship between entities.
SURROGATE primary key
- used to ensure entity integrity, and by making queries simpler - an "artificial" PK that is used to uniquely identify each entity occurrence when there is no good natural key available or when the "natural" PK would include multiple attributes. - used to ensure that relationships between entities can be created more easily - introduced by the designer with the purpose of simplifying the assignment of primary keys to tables. - are usually numeric, they are often automatically generated by the DBMS, and they are free of semantic content (they have no special meaning).
Primary Key
- used to ensure that each row in a table is uniquely identifiable - used to uniquely identify each entity instance.
Characteristics of a Relational Table
-2 dimensional (has rows and columns) -row = 1 occurance -column = attribute (distinct name within that table) -intersection = a data value -all values in a column must conform to the same data format -each column has a specific range of values known as the attribute domain (size, datatype, range) -the order of the rows and columns does not matter -Each row has an attribute (or attributes) that is unique (for that table); a Primary Key
Types of Keys
-Composite -Super -Candidate -Primary -Foreign
Steps of Building an ERD
-Create a detailed narrative or the orgs description of operations -Identify the business rules -Identify the main entities and relationships -Develop the initial ERD -Identify the attributes and PKs that adequately describe the entities -Revise and review the ERD -Once you have discovered the relevant entities you can define the initial set of relationships among them and describe the attributes
Data Management Key Points:
-Data constitutes the building blocks of information. -Information is produced by processing data. -Information is used to reveal the meaning of data. -Accurate, relevant, and timely information is the key to good decision making. -Good decision making is the key to organizational survival in a global environment.
Normalization Levels
-First Normal Form (1NF) -Second Normal Form (2NF) -Third Normal Form (3NF) (Most databases should be 3NF in order to avoid the database anomalies.)
Concurrency control
-Purpose: to ensure that one user's work does not inappropriately influence anther user's work. - No concurrency control technique or mechanism is ideal for all circumstances, all involve trade-offs.
five components of a database system environment
1. Hardware 2. Software 3. People 4. Procedures 5. Data
Negatives of Databases
1. Increased Costs 2. Management Complexity 3. Maintaining Currency 4. Vendor Dependence 5. Frequent upgrading/replacement
4 complex database technologies
1. Very Large Databases 2. Big Databases 3. In memory Databases 4. Cloud Databases
Information
1. ____________________ is the result of processing raw data to reveal its meaning
The relational data model was developed in the ____.
1970s
The object-oriented data model was developed in the ____.
1980s
If one department chair—a professor—can chair only one department and one department can have only one department chair, then the entities PROFESSOR and DEPARTMENT exhibit a(n) ____________________ relationship.
1:1
Preferred relationship in a relational database is
1:M
The _________ relationship is the relational database norm.
1:M
A table that has all key attributes defined, has no repeating groups, and all its attributes are dependent on the primary key, is said to be in__.
1NF
A table with a composite key, has all key attributes defined, has no repeating groups, and all its attributes are dependent on at least part of the primary key, is said to be in ____.
1NF
From a structural point of view, 2NF is better than ____.
1NF
A table is in ___ if it is in 1NF and it includes no partial dependencies.
2NF
A table that is in 1NF and includes no partial dependencies is said to be in ____.
2NF
Before converting a table into 3NF, it is imperative the table already be in ____.
2NF
A table in 2NF and contains no transitive dependencies is in __.
3NF
A table that is in 2NF and contains no transitive dependencies is said to be in ____.
3NF
For most business transaction databases, we should normalize relations into __.
3NF
For most business transactional databases, we should normalize relations into ____.
3NF
Most designers consider the BCNF as a special case of the ____.
3NF
A table that has all key attributes defined, has no repeating groups, and all its attributes are dependent on the primary key, is said to be in ____.
4NF
A table where all attributes are dependent on the primary key and are independent of each other, and no row contains two or more multivalued facts about an entity, is said to be in ____.
4NF
Some very specialized applications may require normalization beyond the ____.
4NF?
Ad hoc query
A "spur-of-the-moment" question.
entity cluster
A "virtual" entity type used to represent multiple entities and relationships in the ERD. An entity cluster is formed by combining multiple interrelated entities into a single abstract entity object.
entity cluster
A "virtual" entity type used to represent multiple entities and relationships in the ERD. An entity cluster is formed by combining multiple interrelated entities into a single abstract entity object. An entity cluster is considered "virtual" or "abstract" in the sense that it is not actually an entity in the final ERD.
data dictionary
A DBMS component that stores metadata—data about data. The ____________________ contains data definitions as well as data characteristics and relationships. May also include data that is external to the DBMS.
Which of the following is an example of structured data?
A Spreadsheet
weak
A ____ entity has a primary key that is partially or totally derived from the parent entity in the relationship.
person's age
A ____ should be a derived attribute.
Field
A character or group of characters (alphabetic or numeric) that has a specific meaning. A field is used to define and store data.
Procedure
A collection of procedural and SQL statements that are assigned a unique name within the schema and stored in the database
File
A collection of related records. For example, a ______ might contain data about the students currently enrolled at Gigantic University.
index
A common practice is to create a(n) ____________________ on any field that is used as a search key, in comparison operations in a conditional expression, or when you want to list rows in a specific order.
Data quality
A comprehensive approach to ensuring the accuracy, validity, and timeliness of data.
transitive dependency
A condition in which an attribute is dependent on another attribute that is not part of the primary key.
full functional dependence
A condition in which an attribute is functionally dependent on a composite key but not on any subset of the key.
data independence
A condition in which data access is unaffected by changes in the physical data storage characteristics.
completeness constraint
A constraint that specifies whether each entity supertype occurence must also be a member of at least one subtype.
completeness constraint
A constraint that specifies whether each entity supertype occurrence must also be a member of at least one subtype. The completeness constraint can be partial or total. Partial completeness means that not every supertype occurrence is a member of a subtype; that is, there may be some supertype occurrences that are not members of any subtype. Total completeness means that every supertype occurrence must be a member of at least one subtype.
data anomaly
A data abnormality in which inconsistent changes have been made to a database. For example, an employee moves, but the address change is not corrected in all files in the database.
structural dependence
A data characteristic in which a change in the database schema affects data access, thus requiring changes in all access programs.
structural independence
A data characteristic in which changes in the database schema do not affect data access.
data dependence
A data condition in which data representation and manipulation are dependent on the physical data storage characteristics.
User-defined data type
A data type that a user can define by making it a subclass of a standard type or creating a type that behaves as an object.UDTs may also have defined functions and methods
Operational database
A database designed primarily to support a company's day-to-day operations. Also known as a transactional database, OLTP database, or production database.
Analytical database
A database focused primarily on storing historical data and business metrics used for tactical or strategic decision making. Such analysis typically requires extensive "data massaging" (data manipulation) to produce information on which to base pricing decisions, sales forecasts, market strategies, and so on.
Centralized database
A database located at a single site.
Extensible Markup Language(XML) database
A database system that stores and manages semistructured XML data.
General-purpose database
A database that contains a wide variety of data used in multiple disciplines.
Discipline-specific database
A database that contains data focused on specific subject areas.
Cloud database
A database that is created and maintained using cloud services, such as Microsoft Azure or Amazon AWS.
Multiuser database
A database that supports multiple concurrent users.
Single-user database
A database that supports only one user at a time.
Why is a table whose primary key consists of a single attribute automatically in 2NF when it is in 1NF?
A dependency based on only a part of a composite primary key is called a partial dependency. Therefore, if the PK is a single attribute, there can be no partial dependencies.
partial dependency
A dependency based on only a part of a composite primary key is called a(n) ____________________.
True
A dependency based on only a part of a composite primary key is known as a partial dependency.
False
A dependency of one nonprime attribute on another nonprime attribute is a partial dependency.
system catalog
A detailed system data dictionary that describes all objects in a database.
False
A determinant is any attribute whose value determines other values within a column.
dependency diagram
A diagram that depicts all dependencies found within a given table structure is known as a(n) ____________________.
False
A disadvantage of the relational database management system (RDBMS) is its inability to hide the complexities of the relational model from the user.
Data management
A discipline that focuses on the proper generation, storage, and retrieval of data.
Transaction
A discrete unit of work that must be completely processed or not processed at all
specialization hierarchy
A hierarchy that is based on the top-down process of identifying lower-level, more specific entity subtypes from a higher-level entity supertype. Specialization is based on grouping unique characteristics and relationships of the subtypes.
Outer Join
A join in which rows that do not have matching values in common columns are nevertheless included in the result table
Equi-Join
A join in which the joining condition is based on equality between values in the common columns.Common values appear (redundantly) in the result table
inner join
A join operation in which only rows that meet a given criterion are selected. The join criterion can be an equality condition (natural join or equijoin) or an inequality condition (theta join). The inner join is the most commonly used type of join. Contrast with outer join.
Natural Join
A join that is the same as an equi-join except that one of the duplicate columns is eliminated in the result table
prime attribute
A key attribute, that is, an attribute that is part of a key or is the whole key. See also key attribute.
prime attribute
A key attribute; that is, an attribute that is part of a key or is the whole key. See also key attributes.
secondary key
A key used strictly for data retrieval purposes. For example, customers are not likely to know their customer number (primary key), but the combination of last name, first name, middle initial, and telephone number will probably match the appropriate table row. See also key.
Record
A logically connected set of one or more fields that describes a person, place, or thing. For example, the fields that constitute a __________ for a customer might consist of the customer's name, address, phone number, date of birth, credit limit, and unpaid balance.
distributed database
A logically related database that is stored in two or more physically independent sites.
candidate key
A minimal superkey; that is, a key that does not contain a subset of attributes that is itself a superkey. See key.
composite key
A multiple-attribute key.
Workgroup database
A multiuser database that usually supports fewer than 50 users or is used for a specific department in an organization.
Trigger
A named set of SQL statements that are considered (triggered) when a data modification (i.e insert, update, delete ) or if certain data definitions are encountered. If a condition stated within a trigger is met, then a prescribed action is taken.
NoSQL
A new generation of database management systems that is not based on the traditional relational database model. Designed to handle the unprecedented volume of data, variety of data types and structures, and velocity of data operations that are characteristic of these new business requirements.
Query language
A nonprocedural language that is used by a DBMS to manipulate its data. An example of a query language is SQL.
True
A null is created when you press the Enter key or the Tab key to move to the next entry without making a prior entry of any kind.
set theory
A part of mathematical science that deals with sets, or groups of things, and is used as the basis for data manipulation in the relational model.
A potential problem with the design is that it may have
A performance problem
Database administrator (DBA)
A person or group responsible for establishing policies and procedures to control and protect a database. They work within guidelines set by data administration to control the database structure, manage data changes, and maintain DBMS programs
single-valued
A person's social security number would be an example of a(n) ____________________ attribute.
Structured Query Language(SQL)
A powerful and flexible relational database language composed of commands that enable users to create database and table structures, perform various types of data manipulation and data administration, and query the database to extract useful information.
iterative process
A process based on repetition of steps and procedures.
denormalization
A process by which a table is changed from a higher level normal form to a lower level normal form. Usually done to increase processing speed. Potentially yields data anomalies.
denormalization
A process by which a table is changed from a higher-level normal form to a lower-level normal form, usually to increase processing speed. Denormalization potentially yields data anomalies.
normalization
A process that assigns attributes to entities in such a way that data redundancies are reduced or eliminated.
normalization
A process that assigns attributes to entities so that data redundancies are reduced or eliminated.
existence-independent
A property of an entity that can exist apart from one or more related entities. Such a table must be created first when referencing an existence-dependent table.
existence-dependent
A property of an entity whose existence depends on one or more other entities. In such an environment, the existence-independent table must be created and loaded first because the existence-dependent key cannot reference a table that does not yet exist.
closure
A property of relational operators that permits the use of relational algebra operators on existing tables (relations) to produce new relations.
atomicity
A property of transactions that states that all parts of a transaction must be treated as a single logical unit of work in which all operations must be completed (committed) to produce a consistent database.
cardinality
A property that assigns a specific value to connectivity and expresses the range of allowed entity occurrences associated with am single occurrence of the related entity.
query
A question or task asked by an end user of a database in the form of SQL code. A specific request for data manipulation issued by the end user or the application to the DBMS.
natural key (natural identifier)
A real-world, generally accepted identifier used to identify real-world objects. As its name implies, a natural key is familiar to end users and forms part of their day-to-day business vocabulary.
Join
A relational operation that causes two tables with a common domain to be combined into a single table or view
repeating
A relational table must not contain ____________________ groups.
recursive relationship
A relationship found within a single entity type. For example, an EMPLOYEE is married to an EMPLOYEE or a PART is a component of another PART.
mandatory participation
A relationship in which one entity occurrence must have a corresponding occurrence in another entity. For example, an EMPLOYEE works in a DIVISION. (A person cannot be an employee without being assigned to a company's division.)
identifying relationship
A relationship in which related entities are existence-dependent. Also called a strong relationship or strong identifying relationship because the dependent entity's primary key contains the primary key of the parent entity.
non-identifying relationship
A relationship in which the primary key of the dependent (many side) entity does not contain the primary key of the related parent entity. Also known as a weak relationship.
weak relationship
A relationship in which the primary key of the related entity does not contain a primary key component of the parent entity. Also known as a non-identifying relationship.
What is a relationship, and what three types of relationships exist?
A relationship is an association among (two or more) entities. Three types of relationships exist: one-to-one (1:1), one-to-many (1:M), and many-to-many (M:N or M:M.)
strong (identifying) relationship
A relationship that occurs when two entities are existence-dependent; from a database design perspective, this relationship exists whenever the primary key of the related entity contains the primary key of the parent entity.
dependency diagram
A representation of all data dependencies (primary key, partial, or transitive) within a table.
Business Intelligence
A set of tools and processes used to capture, collect, integrate, store, and analyze data to support business decision making.
Online analytical processing(OLAP)
A set of tools that provide advanced data analysis for retrieving, processing, and modeling data from the data warehouse.
Desktop database
A single-user database that runs on a personal computer.
Boyce-Codd normal form (BCNF)
A special form of third normal form (3NF) in which every determinant is a candidate key. A table that is in BCNF must be in 3NF. See also determinant.
Boyce-Codd normal form (BCNF)
A special type of third normal form (3NF) in which every determinant is a candidate key. A table in BCNF must be in 3NF. See also determinant.
Data warehouse
A specialized database that stores historical and aggregated data in a format optimized for decision support.
Boolean
A specialty field in mathematics, known as ____________________ algebra, is dedicated to the use of logical devices.
Function
A stored subroutine that returns one value and has only input parameters
surrogate key
A system-assigned primary key, generally numeric and auto-incremented.
DROP
A table can be deleted from the database by using the ____________________ command.
third normal form (3NF)
A table is in 3NF when it is in 2NF and no nonkey attribute is functionally dependent on another nonkey attribute; that is, it cannot include transitive dependencies.
True
A table is in BCNF if every determinant in the table is a candidate key.
fourth normal form (4NF)
A table that is in 3NF and contains no multiple independent sets of multivalued dependencies.
hub
A warehouse of data packets housed in a central location on a local area network. It contains multiple ports that copy the data in the data packets to make it accessible to selected or all segments of the network.
existence
A weak entity must be ____________________-dependent.
associative
A(n) ____ entity is composed of the primary keys of each of the entities to be connected.
application
A(n) _____ might be written by a programmer or it might be created through a DBMS utility program
derived
A(n) ____________________ attribute need not be physically stored within the database.
wildcard
A(n) ____________________ character is a symbol that can be used as a general substitute for other characters or commands.
repeating group
A(n) ____________________ derives its name from the fact that a group of multiple entries of the same type can exist for any single key attribute occurrence.
Data Anomaly
A(n) ____________________ develops when all required changes in the redundant data are not made successfully
Data Warehouse
A(n) ____________________ focuses primarily on storing data used to generate information required to make tactical or strategic decisions.
Segment
A(n) ____________________ in a hierarchical model is the equivalent of a record in a file system.
Unique
A(n) ____________________ index is an index in which the index key can have only one pointer value (row) associated with it.
Business Rule
A(n) ____________________ is a brief, precise, and unambiguous description of a policy, procedure, or principle within a specific organization.
DBMS(Database Management System)
A(n) ____________________ is a collection of programs that manages the database structure and controls access to the data stored in the database.
Class
A(n) ____________________ is a collection of similar objects with a shared structure and behavior.
schema
A(n) ____________________ is a group of database objects, such as tables and indexes, that are related to each other.
Data Model
A(n) ____________________ is a relatively simple representation of more complex real-world data structures
Relational Diagram
A(n) ____________________ is a representation of the relational database's entities, the attributes within those entities and the relationships between those entities.
query
A(n) ____________________ is a specific request issued to the DBMS for data manipulation.
Index
A(n) ____________________ is an orderly arrangement used to logically access rows in a table.
join
A(n) ____________________ is performed when data is retrieved from more than one table at a time.
Domain
A(n) ____________________ is the attribute's set of possible values.
Candidate
A(n) ____________________ key can be described as a superkey without unnecessary attributes.
Equijoin
A(n) ____________________ links tables on the basis of an equality condition that compares specified columns of each table.
cascading
A(n) ____________________ order sequence can be created easily by listing several attributes, separated by commas, after the ORDER BY clause.
Data Dictionary
A(n) ____________________ provides a detailed description of all tables found within the user/designer-created database.
binary
A(n) ____________________ relationship exists when two entities are associated.
Strong
A(n) ____________________ relationship is also known as an identifying relationship.
subquery
A(n) ____________________, also known as a nested query or an inner query, is a query that is embedded (or nested) inside another query.
An entity cluster is considered "virtual" or "_____" in the sense that it is not actually an entity in the final ERD.
Abstract
attribute names
According to the data modeling checklist, ____________________ should be unique within the entity.
good decision making
Accurate, relevant, and timely information is the key to _______.
Performance tuning
Activities that make a database perform more efficiently in terms of storage and access speed.
Performance tuning
Activities that make the database perform more efficiently
Transaction begins in server; request is recorded on hard disk drive, transaction copied into actual database, checkpoint file is updated
Airline example
Referential Integrity
All foreign keys must be valid; either null or a value in the PK of another related table
True
All relational tables satisfy the 1NF requirements.
first normal form
All relational tables satisfy the ____________________ requirements.
binary relationship
An ER term for an association (relationship) between two entities. For example, PROFESSOR teaches COURSE.
participants
An ER term for entities that participate in a relationship. For example, in the relationship "PROFESSOR teaches CLASS," the teaches relationship is based on the participants PROFESSOR and CLASS.
ternary relationship
An ER term used to describe an association (relationship) between three entities. For example, a CONTRIBUTOR contributes money to a FUND from which a RECIPIENT receives money.
unary relationship
An ER term used to describe an association within an entity. For example, a COURSE might be a prerequisite to another COURSE.
recursive
An alias is especially useful when a table must be joined to itself in ____________________ queries.
Cannot be further subdivided.
An atomic attribute ____.
foreign key (FK)
An attribute or attributes in one table whose values must match the primary key in another table or whose values must be null. See key.
superkey
An attribute or attributes that uniquely identify each entity in a table. See key.
multi-valued
An attribute representing one or more college degrees belonging to a person would be a(n) ____________________ attribute.
composite attribute
An attribute that can be further subdivided to yield additional attributes. For example, a phone number such as 615-898-2368 may be divided into an area code (615), an exchange number (898), and a four-digit code (2368). Compare to simple attribute.
multivalued attributes
An attribute that can have many values for a single entity occurrence. For example, an EMP_DEGREE attribute might store the string "BBA, MBA, PHD" to indicate three different degrees held.
single-valued attribute
An attribute that can have only one value.
atomicity
An attribute that cannot be further divided is said to display ____________________.
atomic attribute
An attribute that cannot be further subdivided to produce meaningful components. For example, a person's last name attribute cannot be meaningfully subdivided into other name components; therefore, the last name attribute is ...
atomic attribute
An attribute that cannot be further subdivided to produce meaningful components. For example, a person's last name attribute cannot be meaningfully subdivided.
derived attribute
An attribute that does not physically exist within the entity and is derived via an algorithm. For example, the Age attribute might be derived by subtracting the birth date from the current date.
nonkey attribute
An attribute that is not part of a key.
nonprime attribute
An attribute that is not part of a key.
dependent
An attribute whose value is determined by another attribute.
abstract
An entity cluster is considered "virtual" or "____________________" in the sense that it is not actually an entity in the final ERD.
composite entity
An entity designed to transform an M:N relationship into two 1:M relationships. The composite entity's primary key comprises at least the primary keys of the entities that it connects. Also known as a bridge entity. See also linking table.
key
An entity identifier based on the concept of functional dependence; keys may be classified in several ways. See also superkey, candidate key, primary key (PK), secondary key, and foreign key.
____ is a generic entity type that is related to one or more entity subtypes.
An entity supertype
weak entity
An entity that displays existence dependence and inherits the primary key of its parent entity. For example, a DEPENDENT requires the existence of an EMPLOYEE.
False
An implementation-ready data model needn't necessarily contain enforceable rules to guarantee the integrity of the data.
True
An implementation-ready data model should contain a description of the data structure that will store the end-user data.
unique index
An index in which the index key can have only one associated pointer value (row).
Entity
An object of interest to the end user. Corresponds to a table in the relational environment. Represented by a rectangle and name is usually a noun
Database System
An organization of components that defines and regulates the collection, storage, management, and use of data in a database environment. Composed of the five major parts: hardware, software, people, procedures, and data.
strong
Another word for existence-independent is ____.
determinant
Any attribute in a specific row whose value directly determines other values in that row. See also Boyce-Codd normal form (BCNF).
prime attribute
Any attribute that is at least part of a key is known as a(n) ____________________.
Key attribute
Any attribute that is part of a key
determinant
Any attribute whose value determines other values within a row is called a(n) ____________________.
Relationship
Association between entities. Usually defined as a verb. Operate in both directions
True
At the heart of all data systems are the collection, storage, aggregation, manipulation, dissemination, and management of data.
Each column in a relation represents a(n) ____.
Attribute
Dependent
Attribute A determines attribute B (that is, B is functionally ____________________ on A) if all of the rows in the table that agree in value for attribute A also agree in value for attribute B.
Composite Attribute
Attribute that can be further subdivided to yield additional attributes
Single-valued Attribute
Attribute that can only have a single value (not necessarily a simple attribute)
Simple Attribute
Attribute that cannot be subdivided
Derived Attributes
Attribute whose value is calculated (derived) from other attributes. Doesn't need to be physically stored within the database. Sometimes referred to as computed attributes. Decision to store derived attributes depends on processing requirements and the constraints placed on application
____ are characteristics of entities.
Attributes
Candidate
BCNF can be violated only if the table contains more than one ____ key.
primary
Because a partial dependency can exist only if a table's primary key is composed of several attributes, a table whose ____________________ key consists of only a single attribute must automatically be in 2NF if it is in 1NF.
____ relationships are most common.
Binary
_________ relationships are most common
Binary
Correctly determining the cardinality of a relationship by evaluating from
Both ends
What are the requirements that two relations must satisfy in order to be considered union-compatible?
Both must have the same number of attributes (columns) and corresponding attributes (columns) must have the same (or compatible) domains (data types).
Another name for a composite entity is a ____ entity.
Bridge
False
Business rules apply to businesses and government groups, but not to other types of organizations such as religious groups or research laboratories.
what products are included in Product line 1?
CASE could be used in constructing a query that asks
10. The ____ attribute(s) make up the primary key in the table definition: CLASS (CRS_CODE, CLASS_SECTION, CLASS_TIME, CLASS_ROOM, PROF_NUM)
CRS_CODE and CLASS_SECTION
Composite attribute
Can be further subdivided to yield additional attributes
Not null
Can be placed on a column to ensure that every row has a value for that column
Multivalued Attribute
Can have many values. Should not be implemented into a RDBMS. Try to fix by creating a new entity composed of the original mulitvalued attribute's components; make a 1:M relationship to the original entity
A ____ key can be described as a superkey without unnecessary attributes, that is, a minimal superkey.
Candidate
PRODUCT yields all possible pairs of rows from two tables—also known as the ____________________ product.
Cartesian
False
Character data can contain any character or symbol intended for mathematical manipulation.
Field
Character that has specific meaning
Attribute
Characteristics of entities
A(n) ____ is a collection of similar objects with a shared structure and behavior.
Class
The relationship ___ is difficult to establish if you know only one side of the relationship.
Classification
Guaranteed Access
Codd's rule of ____________________ states that every value in a table is guaranteed to be accessible through a combination of table name, primary key value, and column name.
join column(s)
Columns that join two tables. The join columns generally share similar values.
identifying
Composite keys are useful as identifiers of weak entities, where the weak entity has a strong ____________________ relationship with the parent entity.
Only once
Composite primary keys are particularly useful as identifiers of composite entities, where each primary key combination is allowed ____________________ in the M:N relationship.
ERD represents the
Conceptual database as viewed by the end user
Business Rules
Connectivities and cardinalities are usually based on ____________________ rules.
Data
Consists of raw facts. The word raw indicates that the facts have not yet been processed to reveal their meaning.
Multi valued type of attribute cannot be
Created into a DBMS
Oracle
DATE() and SYSDATE are special functions that return today's date in MS Access and ____________________, respectively.
Implicit locks are placed by
DBMS
The ____ serve(s) as the intermediary between the user and the database.
DBMS
the __ serve(s) as the intermediary between the user and the database a. DBMS b. metadata c. end-user data d. programming language
DBMS
Of the following normal forms, ____ is mostly of theoretical interest.
DKNF
exists when the same data are stored unnecessarily at different places.
Data Redundancy
Structured
Data are the result of formatting to facilitate storage of info
A(n) ____________________ provides a detailed description of all tables found within the user/designer-created database.
Data dictionary
Relational System
Data from related tables are combined into one result table or view and then displayed or used as input to a form or report definition
____ exists when different versions of the same data appear in different places.
Data inconsistency
transactions
Data maintenance is defined in units of work called
Computerized file systems
Data processing specialist converted computer file structure from manual system
duplication
Data redundancies are caused by ____________________ of data on every row entry.
True
Data redundancy produces data anomalies.
Unstructured data
Data that exists in its original, raw state; that is, in the format in which it was collected.
Semistructured data
Data that has already been processed to some extent.
Structured data
Data that has been formatted to facilitate storage, use, and information generation.
Semistructured data
Data thats already been processed to some extent
____ databases reflect the ever-growing demand for greater scope and depth in the data on which decision support systems increasingly rely.
Data warehouse?
time-variant data
Data whose values are a function of time. For example, time-variant data can be seen at work when the history of all administrative appointments (date of appointment and date of termination) are tracked.
False
Database designers determine the data and information that yield the required understanding of the entire business.
diagram
Dependencies can be identified with the help of a dependency ____________________.
False
Dependencies that are based on only a part of a composite primary key are called transitive dependencies.
True
Dependency diagrams are very helpful in getting a bird's eye view of all the relationships among a table's attributes.
True
Depending on the sophistication of the application development software, nulls can create problems when functions such as COUNT, AVERAGE, and SUM are used.
Metadata
Describes the data characteristics and the set of relationships that links the data found within the database. For example, the _________________ component stores information such as the name of each data element, the type of values (numeric, dates, or text) stored on each data element, and whether the data element can be left empty.
Verb
Describes the relationship between entities
non-overlapping
Disjoint subtypes are also known as ____________________ subtypes.
A ____ database supports data distributed across several different sites.
Distributed
Noncorrelated subqueries
Do not depend on data from the outer query Execute once for the entire outer query
Optional attribute
Does not require a value, can be left empty
Attributes may share a ____.
Domain
The set of possible values for an attribute is a ____.
Domain
The ___ refers to a specific table row as an entity instance.
ER model
Attribute
Each column in a relation represents a(n) ____________________.
Tuple
Each row in a relation is called a(n) ____________________
True
Each table in a relational database must have a primary key.
A(n) ____ database is used by an organization and supports many users across many departments.
Enterprise
A relationship is an association between ____.
Entities
A(n) ____ represents a particular type of object in the real world.
Entity
Strong entity
Entity can exist apart from all of its related entities; existence dependent. Also called a regular entity
Primary Key (ENTITY INTEGRITY)
Entity integrity describes a condition in which all tuples (i.e., rows or records) within a table are uniquely identified by their primary key. The unique value requirement prohibits a null primary key value, because nulls are not unique. - ensures that each row is uniquely identified by the primary key.
Which model has the highest level of abstraction
Entity relationship
False
Even when a good database blueprint is available, an applications programmer's view of the data should match that of the manager and the end user.
Entity Integrity
Every row in a table has a unique identifier (PK) which has no null values
If an entity can exist apart from one or more related entities, it is said to be ____-independent.
Existence
Weak relationship
Exists if the primary key of the related entity does not contain a primary key component of the parent entity; also known as a non-identifying relationship
Unary Relationship
Exists when an association is maintained within a single entry
data inconsistency
Exists when different and conflicting versions of the same data appear in different places.
Data inconsistency
Exists when different versions of the same data appears in different places.
Strong Relationship
Exists when the primary key of the related entity contains a primary key component of the parent entity; also known as an identifying relationship. Must load the "1" side in the 1:M relationship first
Data redundancy
Exists when the same data is stored unnecessarily at different places.
Binary Relationship
Exists when two entities are associated. Most common type of relationships
FROM
Explicit Join...ON commands are included in the __ clause
Cardinality
Expresses the minimum and maximum number of entity occurrences associated with one occurrence of the related entity. Established by business rules.
Persistent Stored Modules (SQL/PSM)
Extensions defined in SQL:1999 that include the capability to create and drop modules of code stored in the database schema across user sessions
The ____ model is the end users' view of the data environment.
External
1. As rare as 1:1 relationships should be, certain conditions absolutely require their use.
F
1. Data and information are essentially the same thing.
F
10. A table is in BCNF if every determinant in the table is a foreign key.
F
10. Composite attributes make it easier to facilitate detailed queries.
F
10. In an SQL-based relational database, each table is dependent on every other table.
F
10. One disadvantage of the DBMS is that it increases the risk of data security breaches.
F
11. Relationships between entities always operate in one direction.
F
12. A disadvantage of the relational database management system (RDBMS) is its inability to hide the complexities of the relational model from the user.
F
14. In implementation terms, an entity is existence-dependent if it has a mandatory primary key.
F
14. The SELECT operator yields a vertical subset of a table.
F
15. A weak relationship exists if the primary key of the related entity contains at least one primary key component of the parent entity.
F
15. Field refers to a collection of related records.
F
16. Data anomaly is defined as the condition in which all of the data in the database are consistent with the real-world events and conditions.
F
16. In a natural join, the column on which the join was made occurs twice in the new table.
F
17. Dependencies that are based on only a part of a composite primary key are called transitive dependencies.
F
17. Structural dependence exists when it is possible to make changes in the file structure without affecting the application program's ability to access the data.
F
18. An advantage of database systems is that you needn't perform frequent updates and apply latest patches.
F
18. Referential integrity and participation are both bidirectional, meaning that they must be addressed in both directions along a relationship.
F
18. The external model is the representation of the database as "seen" by the DBMS.
F
19. The onetomany (1:M) relationship is easily implemented in the relational model by putting the foreign key of the "1" side in the table of the "many" side as a primary key.
F
2. An implementation-ready data model needn't necessarily contain enforceable rules to guarantee the integrity of the data.
F
2. Normalization produces a lower normal form.
F
2. The Crow's Foot notation is less implementationoriented than the Chen notation.
F
20. Converting a database format from 1NF to 2NF is a complex process.
F
20. The existence of a mandatory relationship indicates that the minimum cardinality is 0 or 1 for the mandatory entity.
F
22. The process of database design is a sequential process.
F
24. A determinant is any attribute whose value determines other values within a column.
F
26. Data stored at their highest level of granularity are said to be atomic data.
F
27. Atomic attributes are attributes that can be further subdivided.
F
3. Data is the result of processing raw facts to reveal its meaning.
F
3. Normalization is a process that is used for changing attributes to entities.
F
3. The order of the rows and columns is important to the DBMS.
F
30. The combination of normalization and ER modeling yields a useful ERD, whose entities can be translated into appropriate relationship structures.
F
31. A good relational DBMS excels at managing denormalized relations.
F
33. Normalization purity is often easy to sustain in the modern database environment.
F
35. Attributes should clearly define participation, connectivity, and document cardinality.
F
4. Character data can contain any character or symbol intended for mathematical manipulation.
F
4. When data are entered into a form and saved, they are placed in the underlying database as knowledge.
F
5. Even when a good database blueprint is available, an applications programmer's view of the data should match that of the manager and the end user.
F
5. The row's range of permissible values is known as its domain.
F
7. Database designers determine the data and information that yield the required understanding of the entire business.
F
7. Reporting anomalies in a table can cause a multitude of problems for managers and can be fixed through application programming.
F
7. Software vendors have adopted the Chen representation because of its compact representation.
F
7. The idea of determination is unique to the database environment.
F
8. Business rules apply to businesses and government groups, but not to other types of organizations such as religious groups or research laboratories.
F
8. Database programming languages receive all application requests and translate them into the complex operations required to fulfill those requests.
F
8. Only a single attribute, not multiple attributes, can define functional dependence.
F
9. The Crow's Foot notation easily identifies multivalued attributes.
F
Participation
Failure to understand the distinction between mandatory and optional ____________________ in relationships might yield designs in which awkward (and unnecessary) temporary rows (entity instances) must be created just to accommodate the creation of required entities.
A dependency of one nonprime attribute on another nonprime attribute is partial dependency
False
A determinant is any attribute whose value determines other values within a column.
False
A foreign key must exist in both tables that have a relationship
False
A foreign key must exist in both tables that have a relationship.
False
A good relational DBMS excels at managing denormalized relations.
False
A manager and a programmer usually have the same view of the same data.
False
A query language is a procedural language.
False
A table is in BCNF if every determinant in the table is a foreign key.
False
A weak relationship exists if the primary key of the related entity contains at least one primary key component of the parent entity.
False
All RDBMSs enforce integrity rules automatically.
False
All simple attributes are also single-valued.
False
All simple attributes are single valued
False
An ERM is dependent on the database type.
False
An operational database is sometimes referred to as an enterprise database.
False
Atomic attributes are attributes that can be further divided
False
Atomic attributes are attributes that can be further subdivided.
False
Attributes are types of entities.
False
Attributes cannot share a domain.
False
Attributes do not have a domain
False
Attributes do not have a domain.
False
Attributes have a domain that specifies the data type of the attribute.
False
Attributes should clearly define participation, connectivity, and document cardinality.
False
Because the relational model uses attribute values to establish relationships among tables, many database users correctly assume that the term relation refers to such relationships
False
Because the relational model uses attribute values to establish relationships among tables, many database users correctly assume that the term relation refers to such relationships.
False
Business rules apply to businesses and government groups, but not to other types of organizations such as religious groups or research laboratories.
False
Character data can contain any character or symbol intended for mathematical manipulation
False
Character data can contain any character or symbol intended for mathematical manipulation.
False
Converting a database format from 1NF to 2NF is a complex process.
False
Corporations use only structured data.
False
Data and information are the same thing
False
Data modeling starts with a very complex representation, and as knowledge of the problem is gained, the model is simplified.
False
Data that display data inconsistency are referred to as lacking data cohesion.
False
Database designers determine the data and information that yield the required understanding of the entire business.
False
Database programming languages receive all application requests and translate them into the complex operations required to fulfill those requests.
False
Denormalization is a process for assigning attributes to entities.
False
Dependencies that are based on only a part of a composite primary key are called transitive dependencies
False
Dependencies that are based on only a part of a composite primary key are called transitive dependencies.
False
Derived attributes are stored in a special database table.
False
Disjoint subtypes are subtypes that contain nonunique subsets of the supertype entity set.
False
Eat model is depended on the database tupe
False
End-user interfaces require the end user to manually generate SQL code.
False
Entity subtypes do not inherit the relationships in which the supertype entity participates
False
Entity subtypes do not inherit the relationships in which the supertype entity participates.
False
Generalization is based on grouping unique characteristics and relationships of the subtypes.
False
Ideally, a primary key is composed of several attributes.
False
If a table in 1NF has a single-attribute primary key, then the table is automatically in 2NF
False
Implementing non-overlapping subtypes requires the use of one discriminator attribute for each subtype
False
Implementing non-overlapping subtypes requires the use of one discriminator attribute for each subtype.
False
In Chen notation, entities and relationships must be oriented horizontally.
False
In Chen notation, there is no way to represent cardinality.
False
In a natural join, the column on which the join was made occurs twice in the new table
False
In a natural join, the column on which the join was made occurs twice in the new table.
False
In a page-level lock, the DBMS will lock an entire diskpage; also known as a "table level lock".
False
In a relational model, if A determines B, C, and D, you write A = B, C, D
False
In a relational model, if A determines B, C, and D, you write A = B, C, D.
False
In an ER diagram, primary keys are usually bolded.
False
In an SQL-based relational database, each table is dependent on another.
False
In specialization hierarchies with multiple levels of supertype/subtypes, a lower-level supertype inherits all of the attributes and relationships from all of its upper-level subtypes.
False
Many-to-many relationships are easily represented using a hierarchical model.
False
Normalization is a process that is used for changing attributes to entities.
False
Normalization is a very important database design ingredient and the highest level is always the most desirable.
False
Normalization produces a lower normal form.
False
Normalization purity is easy to sustain in the modern database environment.
False
One advantage of a database system over previous data management approaches is that the database system is considerably less complex.
False
Only a single attribute can define functional dependence
False
Only a single attribute, not multiple attributes, can define functional dependence
False
Only a single attribute, not multiple attributes, can define functional dependence.
False
Overlapping subtypes are subtypes that contain a unique subset of the supertype entity set.
False
Referential and entity integrity are two names for the same thing
False
Referential and entity integrity are two names for the same thing.
False
Relationships operate in one direction
False
Relationships operate only in one direction.
False
Repeating groups must be eliminated by making sure that each column defines a single entity.
False
Software vendors have adopted the Chen representation because of its compact representation.
False
The Crow's Foot model is less implementation-oriented than the Chen model.
False
The DBMS can easily handle multivalued attributes.
False
The DBMS reveals much of the database's internal complexity to the application programs and users.
False
The SELECT operator yields a vertical subset of a table
False
The SELECT operator yields a vertical subset of a table.
False
The combination of normalization and ER modeling yields a useful ERD, whose entities may now be translated into appropriate relationship structures.
False
The existence of a mandatory relationship indicates that the minimum cardinality is 0 or 1 for the mandatory entity.
False
The hierarchical model is software-independent.
False
The idea of determination is unique to the database environment
False
The idea of determination is unique to the database environment.
False
The number of users determines whether the DBMS is classified as single-system or multiuser.
False
The one-to-many (1:M) relationship is easily implemented in the relational model by putting the foreign key of the "1" side in the table of the "many" side as a primary key
False
The one-to-many (1:M) relationship is easily implemented in the relational model by putting the foreign key of the "1" side in the table of the "many" side as a primary key.
False
The order of the rows and columns is important to the DBMS.
False
The property of subtype discriminator enables an entity supertype to inherit the attributes and relationships of the subtype
False
The property of subtype discriminator enables an entity supertype to inherit the attributes and relationships of the subtype.
False
The relational model is hardware-dependent and software-independent.
False
The relationships depicted within the specialization hierarchy are sometimes described in terms of is-a relationships
False
There is never a good reason to use null values in a database.
False
To model time-variant data, you must create a new entity in a M:N relationship with the original entity.
False
True or False The one-to-many (1:M) relationship is easily implemented in the relational model by putting the foreign key of the "1" side in the table of the "many" side as a primary key.
False
True or False. Only a single attribute, not multiple attributes, can define functional dependence.
False
True or false The order of the rows and columns is important to the DBMS.
False
Within a specialization hierarchy, a supertype can exist only within the context of a subtype.
False
Within an specialization hierarchy, a supertype can exist only within the context of a subtype.
False
Information implies familiarity, awareness, and understanding knowledge as it applies to an environment.
False KNOWLEDGE implies familiarity, awareness and understanding of INFORMATION as it applies to an environment.
Structural dependence exists when it is possible to make changes in the file structure without affecting the application program's ability to access the data.
False Structural INDEPENDENCE exists when you can change the file structure without affecting the application's ability to access the data.
One disadvantage of the DBMS is that it increases the risk of data security breaches.
False The DBMS DECREASES the security risk.
Data and information are essentially the same thing.
False. Data is raw fact. Information is processed data.
Create a detailed narrative of the organizations description of operations
First step of building an ERD
Placeholder
Flag
3NF
For most business transactional databases, we should normalize relations into ____.
____ keys work with primary keys to properly implement relationships in the relational model.
Foreign
Many-to-Many
Fortunately, the problems inherent in the ____________________ relationship can easily be avoided by creating a composite entity.
GROUP BY
Frequency distributions can be created quickly and easily using the SQL ____________________ clause.
time-variant data
From a data modeling point of view, ____________________ refer to data whose values change over time and for which you must keep a history of the data changes.
Derived
From a strictly database point of view, ____ attribute values can be calculated when they are needed to write reports or invoices.
The attribute B is ____ the attribute A if each value in column A determines one and only one value in column B.
Functionally dependent on
____ is the bottom-up process of identifying a higher-level, more generic entity supertype from lower-level entity subtypes.
Generalization
Data models
Graphical system capturing nature and relationship of data
Embedded SQL
Hard-coded sql statements included in a program written in another language, such as C or Java.
RBDMS
Hierarchical structure where it's at the top and records are at the bottom
The SQL command that lets you insert rows into a table is ____.
INSERT
___ yields only the rows that appear in both tables.
INTERSECT
Composite keys are useful as identifiers of weak entities, where the weak entity has a strong_____ relationship with the parent entity.
Identifying
relationships
Identifying the attributes of the entities helps you better understand the ____________________ among entities.
recu
If an employee within an EMPLOYEE entity has a relationship with itself, that relationship is known as a ____ relationship.
RDBMS
If database tables are treated as though they were files in a file system, the ___________________ never has a chance to demonstrate its superior data-handling capabilities.
1:1
If one department chair—a professor—can chair only one department and one department can have only one department chair, then the entities PROFESSOR and DEPARTMENT exhibit a(n) ____________________ relationship.
Natural identifier
If one exists, a data modeler uses a ____ as the primary key of the entity being modeled.
True
If the attribute (B) is functionally dependent on a composite key (A) but not on any subset of that composite key , the attribute (B) is fully functionally dependent on (A).
Existence-dependent
If the entity can exist in the database only when it is associated with another related entity occurrence; has a mandatory foreign key (foreign key attribute cannot be null)
Referential integrity
If the foreign key contains a value, that value refers to an existing valid row in another relation
Referential
If the foreign key contains either matching values or nulls, the table that makes use of that foreign key is said to exhibit ____________________ integrity
null
If you add a new column to a table that already has rows, the existing rows will default to a value of ____________________ for the new column.
unique index
If you use a surrogate key, you must ensure that the candidate key of the entity in question performs properly through the use of "____________________" and "not null" constraints.
SMALLINT
If your integer values are relatively small, use ____________________ instead of INT.
DBMS provides these advantages:
Improved data sharing. Improved data security. Better data integration. Minimized data inconsistency. Improved data access. Improved decision making. Increased end-user productivity.
Natural
In A ____ key is a real-world, generally accepted identifier used to uniquely identify real- world objects.
Small Circle
In Crow's Foot notation, an optional relationship between entities is shown by drawing a(n) ____________________ on the side of the optional entity.
optional participation
In ER modeling, a condition in which one entity occurrence does not require a corresponding entity occurrence in a particular relationship.
composite identifier
In ER modeling, a key composed of more than one attribute.
optional attribute
In ER modeling, an attribute that does not require a value; therefore, it can be left empty.
required attribute
In ER modeling, an attribute that must have a value. In other words, it cannot be left empty.
Correlated subquery
In SQL, a subquery in which processing the inner query depends on data from the outer query
Conditional
In SQL, all ____________________ expressions evaluate to true or false.
null
In SQL, the absence of an attribute value. Note that a null is not a blank.
fourth normal form
In ____________________ no row may contain two or more multivalued facts about an entity.
Crows Foot Notation
In ____________________, a three-pronged symbol represents the "many" side of the relationship.
Chen Notation
In ____________________, relationships are represented by a diamond connected to the related entities through a relationship line.
one
In a 1:M relationship, you must always create the table for the ____________________ side first.
partial completeness
In a generalization hierarchy, means that not every supertype occurrence is a member of a subtype; that is, there may be some supertype occurrences that are not members of any subtype.
total completeness
In a generalization/specialization hierarchy, a condition in which every supertype occurrence must be a member of at least one subtype.
entity supertype
In a generalization/specialization hierarchy, a generic entity type that contains the common characteristics of entity subtypes.
entity subtype
In a generalization/specialization hierarchy, a subset of an entity supertype.
entity supertype
In a generalization/specialization hierarchy, refers to a generic entity type that contains the common characteristics of entity subtypes.
entity subtype
In a generalization/specialization hierarchy, refers to a subset of an entity supertype where the entity supertype contains the common characteristics and the entity subtypes contain the unique characteristics of each entity subtype.
surrogate
In a real-world environment, changing granularity requirements might dictate changes in primary key selection, and those changes might ultimately require the use of ____________________ keys.
repeating group
In a relation, a characteristic describing a group of multiple entries of the same type for a single key attribute occurrence. For example, a car can have multiple colors for its top, interior, bottom, trim, and so on.
repeating group
In a relation, a characteristic describing a group of multiple entries of the same type that exist for a single key attribute occurrence. For example, a car can have multiple colors (top, interior, bottom, trim, and so on).
Data integrity
In a relational database, a condition in which the data in the database complies with all entity and referential integrity constraints.
Attribute
In a relational table, each column has a specific range of values known as the ____________________ domain.
overlapping subtype
In a specialization hierarchy, describes a condition where each entity instance (row) of the supertype can appear in more than one subtype.
disjoint subtype (non-overlapping subtype)
In a specialization hierarchy, refers to a unique and non-overlapping subtype entity set.
identifiers
In an ERM, unique names of each entity instance. In the relational model, such identifiers are mapped to primary keys in tables.
True
In an SQL-based relational database, rows in different tables are related based on common values in common attributes
domain
In data modeling, the construct used to organize and describe an attribute's set of possible values.
Data Processing
In early computer file systems, the ____________________ created computer file structures, wrote the software that managed the data within the structures, and designed application programs that produced reports based on the file data.
partial dependency
In normalization, a condition in which an attribute is dependent on only a portion (subset) of the primary key.
Method
In object-oriented terms, a(n) ____________________ defines an object's behavior.
(min, max)
In the ERD, cardinality is indicated using the ____ notation.
query
In the SQL environment, the word ____________________ covers both questions and actions.
True
In the context of data models, an entity is a person, place, thing, or event about which data will be collected and stored.
availability
In the context of data security, it refers to the accessibility of data whenever required by authorized users and for authorized purposes.
True
In the context of partial dependencies, data redundancies occur because every row entry requires duplication of data.
inheritance
In the object-oriented data model, the ability of an object to inherit the data structure and methods of the classes above it in the class hierarchy. See also class hierarchy.
islands of information
In the old file system environment, pools of independent, often duplicated, and inconsistent data created and managed by different departments.
Attributes
In the original ERM described by Chen, relationships do not contain ____________________.
Keys
In the relational model, ____________________ are important because they are used to ensure that each row in a table is uniquely identifiable.
tuple
In the relational model, a table row.
linking table
In the relational model, a table that implements an M:M relationship. See also composite entity.
primary key (PK)
In the relational model, an identifier composed of one or more attributes that uniquely identifies a row. Also, a candidate key selected as a unique entity identifier. See also key.
existence-dependent
In the relationship "EMPLOYEE claims DEPENDENT" the DEPENDENT entity is ____________________ on the EMPLOYEE entity.
SELECT
Include each attribute after the ____ keyword
API provides data structure
Independence
Relationship Degree
Indicates the number of entities or participants associated with a relationship
_____ is the result of processing raw data to reveal its meaning.
Information
derived
Instead of storing a person's age, it is better to store the date of birth and use the difference between that value and the system date as a(n) ____________________ attribute.
Data warehousing - >100, TB-PB
Integrated decision support system derived from various operational databases
____ yields only the rows that appear in both tables.
Intersect
Information
Is used to reveal the meaning of data
True
It is possible for a table in 2NF to exhibit transitive dependency, where the primary key may rely on one or more nonprime attributes to functionally determine other nonprime attributes.
A(n) ____ process is based on repetition of processes and procedures
Iterative
According to naming conventions described in Chapter 2, ____ would be the best name for a column representing the charges per hour in a table named JOB.
JOB_CHG_HOUR
____ is the body of information and facts about a specific subject.
Knowledge
Record
Logically connected set of fields that describes person place thing
Relational database model enables you to view data
Logically instead of physically
The relational database model enables you to view data ____ rather than ____.
Logically, physically
In a relational database, you cannot implement
M:M
Composite primary keys are particularly useful as identifiers of composite entities, where each primary key combination is allowed only once in the ____ relationship.
M:N
True
M:N relationships are not appropriate in a relational model.
Correlated subqueries
Make use of data from the outer query Execute once for each row of the outer query Can use the EXISTS operator
Processing Speed
Mean minimal access time which may be achieved by minimizing the number and complexity of logically desirable relationships. High processing speeds are often a top priority in a database design. Forced to include derived attributes in the design
Weak Entities
Meets two conditions. Entity is existence dependent and the entity has a primary key that is partially or totally derived from the parent entity in the relationship. Strong (identifying) relationship indicates that the related entity is weak.
____ provide(s) a description of the data characteristics and the set of relationships that link the data found within the database.
Metadata
Binary relationships
Most common
semistructured
Most data that can be encountered are best classified as _____ .
____ attributes can have many values.
Multivalued
Required attribute
Must have a value, cannot be left empty
Costs and Risks of Database Approach
New, specialized personnel Installation and management cost andcomplexity Conversion costs Need for explicit backup and recovery Organizational conflict
ON or WHERE
No matter what form of join you are using, there should be __ or ___ specification
When data is stored in many spreadsheets
No sync, nulls, and redundancies occur
False
Normalization is a process that is used for changing attributes to entities.
False
Normalization is a very important database design ingredient, and the highest level is always the most desirable.
False
Normalization produces a lower normal form.
Entities
Normalization represents a micro view of the ____ within the ERD.
normal
Normalization works through a series of stages called ___________________ forms.
True
Normalization works through a series of stages called normal forms.
A derived attribute
Not stored within the database
Entities
Noun form describing a person, place, event, or concept
In an outer join, the matched pairs would be retained and any unmatched values in the other table would be left ____.
Null
Relational databases minimize
Null entries and duplicate entries
design trap
Occurs when a relationship is improperly or incompletely identified and, therefore, is represented in a way that is not consistent with the real world. The most common design trap is known as a fan trap.
False
One advantage of a database system over previous data management approaches is that the database system is considerably less complex.
An entity identifier is composed of
One attribute
False
One disadvantage of the DBMS is that it increases the risk of data security breaches.
Optional Participation
One entity occurrence does not require a corresponding entity occurrence in a particular relationship. Minimum cardinality is 0 for the optional entity (Optionality)
Mandatory Participation
One entity occurrence requires a corresponding entity occurrence in a particular relationship
Recursive relationship
One in which a relationship can exist between occurrences of the same entity set
Identifiers
One or more attributes that uniquely identify each entity instance (ex: primary key)
____ is a set of tools that work together to provide an advanced data analysis environment for retrieving, processing, and modeling data from the data warehouse.
Online analytical processing
False
Only a single attribute, not multiple attributes, can define functional dependence.
Logical data
Only has true false values
Within a specialization hierarchy, every subtype can have ____ supertype(s) to which it is directly related.
Only one
Participation is ____ if one entity occurrence does not require a corresponding entity occurrence in a particular relationship
Optional
The term "____" is used to label any condition in which one or more optional relationships exist.
Optionality
RDBMS Vendors
Oracle, ibm, Microsoft SQL, MySQL
Subtypes that contain nonunique subsets of the supertype entity set are known as ____ subtypes.
Overlapping
Cartesian
PRODUCT yields all possible pairs of rows from two tables—also known as the ____________________ product.
In the following table description, ____ is the primary key. PRODUCT (PROD_CODE, PROD_DESCRIPT, PROD_PRICE, PROD_ON_HAND, VEND_CODE)
PROD_CODE
____ completeness means that not every supertype occurrence is a member of a subtype.
Partial
Optional
Participation is ____________________ if one entity occurrence does not require a corresponding entity occurrence in a particular relationship.
A ____ should be a derived attribute.
Person's age
Entity
Person, place, thing; Represents a particular object in the real world; nouns
The preferred placement for a foreign key when working with a 1:1 relationship is ____.
Place a foreign key in one of the entities
____ logic, used extensively in mathematics, provides a framework in which an assertion (statement of fact) can be verified as either true or false.
Predicate
The most important characteristic of an entity is its ____ key, used to uniquely identify each entity instance.
Primary
Composite Identifier
Primary key composed of more than one attribute
Iterative Process
Process based on repetition of processes and procedures. Database design is iterative
Advantages of the Database Approach
Program-data independence Planned data redundancy Improved data consistency Improved data sharing increased application development productivity Enforcement of standards Improved data quality Improved data accessibility and responsiveness Reduced program maintenance Improved decision support
warehousing
Proper data ____________________ design requires carefully defined and controlled data redundancies to function properly.
IN
Qualifications such as <ANY or >= ALL instead of ___ are also useful
A(n) _____ is a specific request issued to the DBMS for data manipulation.
Query
The response of the dbms to a query is
Query result set
If database tables are treated as though they were files in a file system, the _____________________________________________ never has a chance to demonstrate its superior data-handling capabilities.
RDBMS (relational database management system)
True
RDBMSs enforce integrity rules automatically.
Data can temporarily be moved from
Ram to hard disk drive
1:1 relationship should be
Rare in any relational database design
Formatted
Raw data must be properly ____________________ for storage, processing and presentation.
formatted
Raw data must be properly ____________________ for storage, processing and presentation.
True
Raw data must be properly formatted for storage, processing and presentation.
End user data is
Raw facts of interest to the end user
____ relationships occur when there are multiple relationship paths between related entities.
Redundant
Foreign Key (REFERENTIAL INTEGRITY)
Referential integrity describes a condition in which a foreign key value has a match in the corresponding table, or in which the foreign key value may be null (depending upon the business rules). - means that, if the foreign key contains a value, that value refers to an existing valid tuple (row) in another relation.
EER diagram (EERD)
Refers to the entity-relationship diagram resulting from the application of extended entity relationship concepts that provide additional semantic content in the ER model.
granularity
Refers to the level of detail represented by the values stored in a table's row. Data stored at their lowest level of granularity are said to be atomic data.
True
Relational models view data as part of a table or collection of tables in which all key values must be identified.
Verb associating two nouns in a business rule
Relationship in a data model
Participation
Relationship strength depends on how the primary key of the related entity is formulated, while the relationship ____________________ depends on how the business rule is written.
True
Repeating groups must be eliminated by ensuring that each row defines a single entity.
False
Reporting anomalies in a table can cause a multitude of problems for managers and can be fixed through application programming.
ERD
Represents the conceptual database as viewed by the end user, depicts the databases main components - entities, attributes and relationships
The SQL command that lets you select attributes from rows in one or more tables is ____.
SELECT
____, also known as RESTRICT, yields values for all rows found in a table that satisfy a given condition.
SELECT
To list all the contents of the PRODUCT table, you would use ____.
SELECT * FROM PRODUCT;
Mobile apps use
SQL NoSQL and Hadoop; HTML5 and JavaScript
COMMIT
SQL command that PERMANENTLY saves data changes to database
ROLLBACK
SQL command that restores the database table content to its last condition, to the condition that existed after the last commit statement
The ______ is the conceptual organization of the entire database as viewed by the database administrator
Schema
index key
See index.
nonkey attribute
See nonprime attribute.
Database should capture the maximum possible
Semantics/meaning
Most data you encounter is
Semi structured
A ____ attribute is one that cannot be subdivided.
Simple
True
Since a partial dependency can exist only if a table's primary key is composed of several attributes, if a table in 1NF has a single-attribute primary key, then the table is automatically in 2NF.
Desktop database
Single user database
extended entity relationship model (EERM)
Sometimes referred to as the enhanced entity relationship model; the result of adding more semantic constructs (entity supertypes, entity subtypes, and entity clustering) to the original entity relationship (ER) model.
unique
Specialization is based on grouping ____________________ characteristics and relationships of the subtypes.
Databases
Specialized structures that allow computer-based systems to store, manage, and retrieve data very quickly.
Dynamic SQL
Specific SQL code generated on the fly while an application is processing
Another word for existence-independent is ____.
Strong
Spreadsheet
Structured data
natural
Surrogate primary keys are especially helpful when there is no ____ key.
1. The practical significance of taking the logical view of a database is that it serves as a reminder of the simple file concept of data storage.
T
1. The process of database design is a sequential process.
T
10. A null is created when you press the Enter key or the Tab key to move to the next entry without making a prior entry of any kind.
T
11. A dependency based on only a part of a composite primary key is known as a partial dependency.
T
11. Depending on the sophistication of the application development software, nulls can create problems when functions such as COUNT, AVERAGE, and SUM are used.
T
11. In an SQL-based relational database, rows in different tables are related based on common values in common attributes
T
12. A data warehouse can store data derived from many sources.
T
12. A table is in fourth normal form if it is in third normal form and has no independent multivalued dependencies.
T
12. Connectivities and cardinalities are established by concise statements known as business rules.
T
12. RDBMSs enforce integrity rules automatically.
T
13. Relational algebra defines the theoretical way of manipulating table contents using relational operators.
T
13. Relational models view data as part of a table or collection of tables in which all key values must be identified.
T
13. The same data might be simultaneously structured and unstructured depending on the intended processing.
T
14. The objective of normalization is to ensure that each table conforms to the concept of well-formed relations.
T
15. M:N relationships are not appropriate in a relational model.
T
15. Repeating groups must be eliminated by ensuring that each row defines a single entity.
T
15. The DIFFERENCE operator subtracts one table from the other.
T
16. Dependency diagrams are very helpful in getting a bird'seye view of all the relationships among a table's attributes.
T
16. In a 1:M relationship, to avoid the possibility of referential integrity errors, the data of the "1" side must be loaded first.
T
16. Today, most relational database products can be classified as object/relational.
T
17. The DIVIDE operation uses one singlecolumn table (e.g., column "a") as the divisor and one twocolumn table (e.g., columns "a" and "b") as the dividend.
T
17. The network model has structural level dependence.
T
17. Unary relationships are common in manufacturing industries.
T
18. A data dictionary is sometimes described as "the database designer's database" because it records the design decisions about tables and their structures.
T
18. All relational tables satisfy the 1NF requirements.
T
19. A weak entity has a primary key that is partially or totally derived from the parent entity in the relationship.
T
19. In the context of partial dependencies, data redundancies occur because every row entry requires duplication of data.
T
19. One disadvantage of a database system over previous data management approaches is increased costs.
T
2. Data processing can be as simple as organizing data to reveal patterns.
T
2. You can think of a table as a persistent representation of a logical relation.
T
20. As rare as 1:1 relationships should be, certain conditions absolutely require their use.
T
21. Since a partial dependency can exist only if a table's primary key is composed of several attributes, if a table in 1NF has a single-attribute primary key, then the table is automatically in 2NF.
T
21. To implement a small database, a database designer must know the "1" and the "M" sides of each relationship and whether the relationships are mandatory or optional.
T
22. A table is in 2NF if it is in 1NF, and it includes no partial dependencies.
T
23. It is possible for a table in 2NF to exhibit transitive dependency, where the primary key may rely on one or more nonprime attributes to functionally determine other nonprime attributes.
T
28. Normalization should be part of the design process.
T
29. Normalization represents a micro view of the entities within the ERD.
T
3. An entity in the entity relationship model corresponds to a table in the relational environment.
T
3. An implementation-ready data model should contain a description of the data structure that will store the end-user data.
T
32. The advantage of higher processing speed must be carefully weighed against the disadvantage of data anomalies.
T
34. Unnormalized database tables often lead to various data redundancy disasters in production databases.
T
4. In order to meet performance requirements, portions of the database design may need to be occasionally denormalized.
T
4. In the entity relationship model, a table row corresponds to an entity instance.
T
4. Within the database environment, a data model represents data structures with the purpose of supporting a specific problem domain.
T
5. Data constitute the building blocks of information.
T
5. Denormalization produces a lower normal form.
T
5. In the Chen and Crow's Foot notations, an entity is represented with a rectangle containing the entity's name.
T
6. Each table in a relational database must have a primary key.
T
6. In the context of data models, an entity is a person, place, thing, or event about which data will be collected and stored.
T
6. In the original Chen notation, each attribute is represented by an oval with the attribute name connected to an entity rectangle with a line.
T
6. Metadata describe the data characteristics and the set of relationships that links the data found within the database
T
7. The only way to access the data in a database is through the DBMS.
T
8. A composite identifier is a primary key composed of more than one attribute.
T
8. Data redundancy produces data anomalies.
T
9. A table is in BCNF if every determinant in the table is a candidate key.
T
9. If the attribute (B) is functionally dependent on a composite key (A) but not on any subset of that composite key, the attribute (B) is fully functionally dependent on (A).
T
Because a partial dependency can exist only if a table's primary key is composed of several attributes, if a table in 1NF has a single-attribute primary key, then the table is automatically in 2NF
T
A(n) ____ is perceived as a two-dimensional structure composed of rows and columns.
Table
unique values
The "____" characteristic of a primary key states that: The PK must uniquely identify each entity instance. A primary key must be able to guarantee unique values. It cannot contain nulls.
security-compliant
The "____" characteristic of a primary key states that: The selected primary key must not be composed of any attribute(s) that might be considered a security risk or violation. For example, using a Social Security number as a PK in an EMPLOYEE table is not a good idea.
Conceptual
The Chen model is specially useful to illustrate some of the ____________________ elements of database design.
Implementation
The Crow's Foot model is more ____________________-oriented than the Chen model.
Solid
The Crow's Foot notation depicts the strong relationship with a(n) ____________________ line between the entities.
(1:1)
The Crow's foot symbol with two parallel lines indicates ____ cardinality.
Qualifier
The _____NOT, ANY, and ALL may be used in front of IN or with logical operators such as =,> and <
System
The ____________________ catalog can be described as a detailed system data dictionary that describes all objects within the database, including data about table names, the table's creator and creation date, the number of columns in each table, the data type corresponding to each column, index filenames, index creators, authorized users, and access privileges.
Completeness
The ____________________ constraint specifies whether each entity supertype occurrence must also be a member of at least one subtype.
Subschema
The ____________________ defines the portion of the database "seen" by the application programs that produce information from the data.
Schema
The ____________________ is the conceptual organization of the entire database as viewed by the database administrator.
extended entity relationship model
The ____________________ is the result of adding more semantic constructs to the original entity relationship (ER) model.
ERD
The ____________________ provides the big picture, or macro view, of an organization's data requirements and operations.
ER model ERM
The ____________________ refers to a specific table row as an entity instance.
1:M
The ____________________ relationship is the relational database norm.
HAVING
The _____________________ clause of the GROUP BY statement operates very much like the WHERE clause in the SELECT statement.
subtype discriminator
The attribute in the supertype entity that determines to which entity subtype each supertype occurrence is related.
key attribute
The attributes that form a primary key.
key attributes
The attributes that form a primary key. See also prime attribute.
100
The basic SQL vocabulary has a fewer than ____________________ words.
connectivity
The classification of the relationship between entities. Classifications include 1:1, 1:M, and M:N.
query result set
The collection of data rows returned by a query.
DBMS (Database Management Systems)
The collection of programs that manages the database structure and controls access to the data stored in the database.
Normalization
The combination of ____________________ and ER modeling yields a useful ERD, whose entities may now be translated into appropriate table structures.
True
The common columns in joined tables are usually the primary key of the dominant table and the foreign key of the dependent table in 1:M relationships.
compromises that include denormalization
The conflicts between design efficiency, information requirements, and processing speed are often resolved through ____.
Design Standards
The database design must conform to design standards that minimize data redundancies, avoid nulls, govern the presentation of all components within the database design, and allow you to work with well defined components and evaluate the interaction of those components
Making sure all business rules are identified is
The database designers job
Second Normal Form (2NF)
The database is in first normal form, all nonkey attributes in the table must be functionally dependent on the entire primary key.
collection of files
The database structure in a DBMS is stored as a ______.
Structured Query Language (SQL)
The de facto query language and data access standard supported by the majority of DBMS vendors
The _____ is the result of adding more semantic constructs to the original entity relationship (ER) model. The enhanced entity relationship mode
The enhanced entity relationship mode or EERM
EER diagram (EERD)
The entity relationship diagram resulting from the application of extended entity relationship concepts that provide additional semantic content in the ER model.
mandatory
The existence of a(n) ____ relationship indicates that the minimum cardinality is at least 1 for the mandatory entity.
First Normal Form (1NF)
The fields contain only atomic values and no repeating groups to try to avoid this.
first normal form (1NF)
The first stage in the normalization process. It describes a relation depicted in tabular format, with no repeating groups and a primary key identified. All nonkey attributes in the relation are dependent on the primary key.
first normal form (1NF)
The first stage in the normalization process. It describes a relation depicted in tabular format, with no repeating groups and with a primary key identified. All nonkey attributes in the relation are dependent on the primary key.
Entity
The following example exhibits ____________________ integrity: The CUSTOMER table's primary key is CUS_CODE. The CUSTOMER primary key column has no null entries, and all entries are unique. Similarly, the AGENT table's primary key is AGENT_CODE, and this primary key column also is free of null entries.
False
The idea of determination is unique to the database environment.
Composite
The index key can have multiple attributes, this is called a(n) ____________________ index.
Relation
The logical view of the relational database is facilitated by the creation of data relationships based on a logical construct known as a(n) ____________________.
consistent
The main concern with redundant relationships is that they remain ____________________ across the model.
The mandatory relationship indicates
The minimum cardinality is at least 1
fan trap
The most common design trap is known as a(n) ____________________.
Primary
The most important characteristic of an entity is its ____ key, used to uniquely identify each entity instance.
Numeric.
The most likely data type for a surrogate key is ____.
True
The network model has structural level dependence.
relationship degree
The number of entities or participants associated with a relationship. A relationship degree can be unary, binary, ternary, or higher.
Cartesian Join
The number of rows is equal to the number of rows in each table, multiplied together
True
The objective of normalization is to ensure that each table conforms to the concept of well-formed relations.
False
The only way to access the data in a database is through the DBMS.
True
The only way to access the data in a database is through the DBMS.
False
The order of the rows and columns is important to the DBMS.
relational schema
The organization of a relational database as described by the database administrator.
its expected use
The organization of data within folders in a manual file system is determined by _____.
Enterprise database
The overall company data representation, which provides support for present and expected future needs.
Data processing (DP) specialist
The person responsible for developing and managing a computerized file processing system.
true, false, dont know
The predicate form is based on three-logic value ____ but allows for more complex operations
place a foreign key in one of the entities
The preferred placement for a foreign key when working with a 1:1 relationship is to ____.
redundancy
The price paid for increased performance through denormalization is a larger amount of ___________________.
entity
The primary key's main function is to uniquely identify a(n) ____ within a table.
anomalies
The problem with transitive dependencies is that they still yield data ____________________.
Database design
The process that yields the description of the database structure and determines the database components. The second phase of the Database Life Cycle.
ANSI defines for events that signal the end of a transaction. Which is a ROLLBACK?
The program is abnormally terminated
Foreign
The proper use of ____________________ keys is crucial to controlling data redundancy.
entity integrity
The property of a relational table that guarantees each entity has a unique value in a primary key and that the key has no null values.
Information requirements
The quest for timely information may be the focus of the database design. Complex info requirements may dictate data transformations and may expand the number of entities and attributes within the design. Database may have to sacrifice some of its clean design structures and/or high transaction speed to ensure maximum info generation
Closure
The relational operators have the property of ____________________; that is, the use of relational algebra operators on existing tables (relations) produces new relations.
When the PK of one entity contains the PK of another
The relationship is strong
Information
The result of processing raw data to reveal its meaning.
determination
The role of a key. In the context of a database table, the statement "A determines B" indicates that knowing the value of attribute A means that the value of attribute B can be looked up.
False
The row's range of permissible values is known as its domain.
second normal form (2NF)
The second stage in the normalization process in which a relation is in 1NF and there are no partial dependencies (dependencies in only part of the primary key).
second normal form (2NF)
The second stage in the normalization process, in which a relation is in 1NF and there are no partial dependencies (dependencies in only part of the primary key).
Domain
The set of possible values for a given attribute
optionality
The term "____" is used to label any condition in which one or more optional relationships exist.
Logical Design
The term ____________________ is used to refer to the task of creating a conceptual data model that could be implemented in any DBMS.
Islands of Information
The term ____________________ refers to scattered locations storing the same basic data.
synonym
The use of different names to identify the same object, such as an entity, an attribute, or a relationship; synonyms should generally be avoided. See also homonym.
homonym
The use of the same name to label different attributes. Homonyms generally should be avoided. Some relational software automatically checks for homonyms and either alerts the user to their existence or automatically makes the appropriate adjustments. See also synonym.
value
The value-expression form requires a match to the ___ expression
physical data format
The way a computer "sees" (stores) data.
logical data format
The way a person views data within the context of a problem domain.
For most purposes in business database design, __ stages are as high as you need to go in the normalization process.
Three
If you have three different transitive dependencies, __ different determinants exist.
Three
____ data refer to data whose values change over time and for which you must keep a history of the data changes.
Time-variant
Flags
To avoid nulls, some designers use special codes, known as ____________________, to indicate the absence of some value.
DROP INDEX
To delete an index, use the ____________________ command.
outer join
To determine which customer did not place order, an _____ is used
context
To reveal meaning, information requires ___________.
Context
To reveal meaning, information requires ____________________.
True
Today, most relational database products can be classified as object/relational.
_____ completeness means that every supertype occurrence must be a member of at least one subtype.
Total
Fishbone diagram shows
Troubleshooting to find the problem
A composite identifier is a primary key composed of more than one attribute
True
A composite identifier is a primary key composed of more than one attribute.
True
A data dictionary contains metadata—data about data
True
A data dictionary contains metadata—data about data.
True
A data dictionary is sometimes described as "the database designer's database" because it records the design decisions about tables and their structures
True
A data dictionary is sometimes described as "the database designer's database" because it records the design decisions about tables and their structures.
True
A data model is usually graphical.
True
A data warehouse can store data derived from many sources.
True
A design trap occurs when a relationship is improperly or incompletely identified and is therefore represented in a way that is not consistent with the real world.
True
A design trap occurs when a relationship is improperly or incompletely identified and, therefore, is represented in a way that is not consistent with the real world.
True
A determinant is any attribute whose value determines other values within a row
True
A left outer join on tables CUSTOMER and AGENT yields all of the rows in the CUSTOMER table, including those that do not have a matching value in the AGENT table
True
A left outer join on tables CUSTOMER and AGENT yields all of the rows in the CUSTOMER table, including those that do not have a matching value in the AGENT table.
True
A null is created when you press the Enter key or the Tab key to move to the next entry without making a prior entry of any kind
True
A null is created when you press the Enter key or the Tab key to move to the next entry without making a prior entry of any kind.
True
A recursive relationship is one in which a relationship can exist between occurrences of the same entity set.
True
A relationship is identified by a name that describes the relationship.
True
A strong relationship exists if the primary key of the related entity contains at least one primary key of the parent entity
True
A table is a persistent representation of a logical relation
True
A table is in 2NF if it is in 1NF and it includes no partial dependencies.
True
A table is in BCNF if every determinant in the table is a candidate key.
True
A table is in fourth normal form if it is in third normal form and has no independent multivalued dependencies.
True
A weak entity has a primary key that is partially or totally derived from the parent entity in the relationship.
True
All attributes are either simple or composite.
True
All relational tables satisfy the 1NF requirements.
True
An entity cluster is a "virtual" entity type used to represent multiple entities and relationships in the ERD.
True
An entity supertype can have disjoint or overlapping entity subtypes.
True
An implementation-ready data model should contain a description of the data structure that will store the end-user data.
True
As rare as 1:1 relationships should be, certain conditions absolutely require their use
True
As rare as 1:1 relationships should be, certain conditions absolutely require their use.
True
At the implementation level, the supertype and its subtype(s) depicted in the specialization hierarchy maintain a 1:1 relationship
True
At the implementation level, the supertype and its subtype(s) depicted in the specialization hierarchy maintain a 1:1 relationship.
True
Atomicity does not indicate permanence
True
Atomicity requires that all portions of the transaction must be treated as a single, logical unit of work in which all operations are applied and completed to produce a consistent database.
True
Because a partial dependency can exist only if a table's primary key is composed of several attributes, if a table in 1NF has a single-attribute primary key, then the table is automatically in 2NF.
True
Business rules must be rendered in writing.
True
Cardinality expresses the minimum and maximum number of entity occurrences associated with one occurrence of the related entity.
True
Certain conditions require 1:1 relationships
True
Connectivities and cardinalities are established by business rules.
True
Corporations use only structured data
True
Current relational database software generally provides only a system catalog (and not a data dictionary)
True
Current relational database software generally provides only a system catalog (and not a data dictionary).
True
DBMSs use indexes for many different purposes
True
DBMSs use indexes for many different purposes.
True
Data constitute the building blocks of info
True
Data constitute the building blocks of information.
True
Data constitutes the building blocks of information.
True
Data dictionary contains metadata- data about data
True
Data model is usually graphical
True
Data processing can be as simple as organizing data to reveal patterna
True
Data processing can be as simple as organizing data to reveal patterns.
True
Denormalization produces a lower normal form
True
Denormalization produces a lower normal form.
True
Dependency diagrams are helpful in getting a birds-eye view of all the relationships among a tables attributes
True
Dependency diagrams are very helpful in getting a bird's-eye view of all the relationships among a table's attributes.
True
Depending on the sophistication of the application development software, nulls can create problems when functions such as COUNT, AVERAGE, and SUM are used
True
Depending on the sophistication of the application development software, nulls can create problems when functions such as COUNT, AVERAGE, and SUM are used.
True
ER diagram represents the conceptual database as viewed by the end user
True
Each row in the relational table is known as an entity instance or entity occurrence in the ER model.
True
Each table in a relational database must have a primary key
True
Each table in a relational database must have a primary key.
True
Entity supertypes and subtypes are organized in a specialization hierarchy.
True
Hard disk is 200 times slower than RAM
True
Historically, a manual file system was composed of a system of file folders and filing cabinets.
True
If the attribute (B) is functionally dependent on a composite key (A) but not on any subset of that composite key, the attribute (B) is fully functionally dependent on (A)
True
If the attribute (B) is functionally dependent on a composite key (A) but not on any subset of that composite key, the attribute (B) is fully functionally dependent on (A).
True
In an SQL-based relational database, rows in different tables are related based on common values in common attributes.
True
In both the Chen and Crow's Foot models, an entity is represented with a rectangle containing the entity's name.
True
In order to meet performance requirements, you may have to denormalize portions of the database design.
True
In the Chen model, a multivalued attribute is connected to the owning entity with a double line.
True
In the original Chen model, each attribute is represented using an oval with the attribute name connected to the entity with a line.
True
Initially the files within a computer file system were similar to manual files.
True
It is possible for a table in 2NF to exhibit transitive dependency
True
It is possible for a table in 2NF to exhibit transitive dependency, where one or more attributes may be functionally dependent on non-key attributes
True
It is possible for a table in 2NF to exhibit transitive dependency, where the primary key may rely on one or more nonprime attributes to functionally determine other nonprime attributes.
True
M:N relationships are not appropriate in a relational model.
True
Manual file system was a filing cabinet
True
Metadata present a more complete picture of the data in the database than the data itself.
True
Most real-world database transactions are formed by more than one database request
True
Normalization represents a micro view of the entities within the ERD.
True
Normalization should be part of the design process.
True
Normalization works through a series of stages called normal forms
True
Normalization works through a series of stages called normal forms.
True
Nulls can create problems when count, average, and sum is used
True
Numeric data are data on which you can perform meaningful arithmetic procedures
True
Numeric data are data on which you can perform meaningful arithmetic procedures.
True
One disadvantage of a database system over previous data management approaches is increased costs.
True
One important inheritance characteristic is that all entity subtypes inherit their primary key attribute from their supertype.
True
One of the disadvantages of the network model was the lack of structural independence.
True
RDBMSs enforce integrity rules automatically
True
RDBMSs enforce integrity rules automatically.
True
Relational models view the data as part of a table or collection of tables in which all key values must be identified
True
Relational models view the data as part of a table or collection of tables in which all key values must be identified.
True
Repeating groups must be eliminated by making sure that each row defines a single entity.
True
Some designs use redundant relationships as a way to simplify the design.
True
Specialization is the top-down process of identifying lower-level, more specific entity subtypes from a higher-level entity supertype.
True
Structural dependence occurs when access to the file is dependent on its structure.
True
Tables must have the same attribute characteristics (the columns and domains must be compatible) to be used in a UNION
True
Tables must have the same attribute characteristics (the columns and domains must be compatible) to be used in a UNION.
True
Tables within a database share common attributes that enable the tables to be linked together
True
Tables within a database share common attributes that enable the tables to be linked together.
True
The DBMS cannot guarantee that the semantic meaning of a transaction truly represents the real-world event.
True
The DBMS cannot handle multi valued attributes
True
The DIFFERENCE operator subtracts one table from the other
True
The DIFFERENCE operator subtracts one table from the other.
True
The DIVIDE operation uses one single-column table (e.g., column "a") as the divisor and one two-column table (e.g., columns "a" and "b") as the dividend
True
The DIVIDE operation uses one single-column table (e.g., column "a") as the divisor and one two-column table (e.g., columns "a" and "b") as the dividend.
True
The ER diagram represents the conceptual database as viewed by the end user.
True
The ER model refers to a specific table row as an entity instance.
True
The ER model refers to a specific table row as an entity occurrence.
True
The advantage of higher processing speed must be carefully weighed against the disadvantage of data anomalies
True
The advantage of higher processing speed must be carefully weighed against the disadvantage of data anomalies.
True
The completeness constraint can be partial or total.
True
The difference operator subtracts one table from the other
True
The entity relationship model is limited to conceptual modeling, with no implementation component.
True
The entity supertype contains the common characteristics and the entity subtypes contain the unique characteristics of each entity subtype.
True
The network model has structural level dependence.
True
The only way to access the data in a database is through the DBMS.
True
The practical significance of taking the logical view of a database is that it serves as a reminder of the simple file concept of data storage
True
The practical significance of taking the logical view of a database is that it serves as a reminder of the simple file concept of data storage.
True
The relationships depicted within the specialization hierarchy are sometimes described in terms of "is-a" relationships.
True
The same data might be simultaneously structured and unstructured depending on the intended processing.
True
The terms data model and database model are often used interchangeably.
True
The word "entity" in the ER model corresponds to a table.
True
Today, most relational database products can be classified as object/relational.
True
True or False An implementation-ready data model should contain a description of the data structure that will store the end-user data.
True
True or False Depending on the sophistication of the application development software, nulls can create problems when functions such as COUNT, AVERAGE, and SUM are used.
True
True or False. Data processing can be as simple as organizing data to reveal patterns.
True
True or False. One disadvantage of a database system over previous data management approaches is increased costs.
True
True or False. RDBMSs enforce integrity rules automatically.
True
True or False. Tables must have the same attribute characteristics (the columns and domains must be compatible) to be used in a UNION
True
True or False. Within the database environment, a data model represents data structures with the purpose of supporting a specific problem domain.
True
Unnormalized database tables often lead to various data redundancy disasters in production databases.
True
We are now said to be entering the "knowledge age."
True
With partial dependencies, data redundancies occur because every row entry requires duplication of data
True
With partial dependencies, data redundancies occur because every row entry requires duplication of data.
True
Within the database environment, a data model represents data structures with the purpose of supporting a specific problem domain.
True
You can think of a table as a persistent representation of a logical relation
True
You can think of a table as a persistent representation of a logical relation.
True
You should always load data from the 1 side of a 1:M relationship.
True
union-compatible
Two or more tables that share the same column names and have columns with compatible data types or domains.
CHAR
U.S. state abbreviations are always two characters, so ____________________(2) is a logical choice for the data type representing a state column.
____ combines all rows from two tables, excluding duplicate rows.
UNION
The SQL command that modifies an attribute's values in one or more table's rows is ____.
UPDATE
A ____ relationship exists when an association is maintained within a single entity.
Unary
Primary keys may be indicated by
Underlining
Non-overlapping subtypes are subtypes that contain a(n) ____ subset of the supertype entity set. unique
Unique
If you use a surrogate key, you must ensure that the candidate key of the entity in question performs properly through the use of the "____" and "not null" constraints.
Unique index
____ data exist in the format in which they were collected.
Unstructured
A database is prone to
Update anomalies
Hierarchical model
Upside down tree; each child has only one parent
Homonym
Use of the same attribute name to label different attributes
Connectivity
Used to describe relationship classification
Associative (composite) entities
Used to implement M:N relationships between two or more entities. Composed of the PKs of each of the entities to be connected
External schema
User View Subsets of Conceptual Schema Can be determined from busniess-function entiy matrics DBA determines schema for different users.
Entity relationship
Uses connectivity to label relationship types
CREATE INDEX
Using the ____________________ command, SQL indexes can be created on the basis of any selected attribute.
Primary Key
Usually, a data modeler uses a natural identifier as the ____________________ of the entity being modeled, assuming that the entity has a natural identifier.
Proper data ____________________ design requires carefully defined and controlled data redundancies to function properly.
Warehousing
BCNF
When a nonkey attribute is the determinant of a key attribute the table is in 3NF but not ____________________.
make sure entities are in normal form before table structures are created.
When designing a database, you should ____. (Hint: It involves normalization, and what should be done prior to creating tables.)
weak
When the PK of one entity does not contain the PK of a related entity, the relationship is ____.
enterprise database
When the database is used by the entire organization and supports many users (more than 50, usually hun- dreds) across many departments
Logical
When you can change the internal model without affecting the conceptual model, you have ____________________ independence.
database creation
With the exception of the ____________________ process, most RDBMS vendors use SQL that deviates little from the ANSI standard SQL.
functional dependence
Within a relation R, an attribute B is functionally dependent on an attribute A if and only if a given value of attribute A determines exactly one value of attribute B. The relationship "B is dependent on A" is equivalent to "A determines B," and is written as AB.
True
Within the database environment, a data model represents data structures with the purpose of supporting a specific problem domain.
Inventory should only have 2, but it display 7 ! Wrong
Wrong
___________________________________ is a special language used to represent and manipulate data elements in a textual format.
XML
Oracle 11g is an example of a(n) ____.
XML/Hybrid data model
attribute names
You can indicate just the attributes that have required values by listing the ____________________ inside parentheses after the table name.
True
You can think of a table as a persistent representation of a logical relation.
time-variant
____ data refer to data whose values change over time and for which you must keep a history of the data changes.
Data warehouse
____ databases reflect the ever-growing demand for greater scope and depth in the data on which decision support systems increasingly rely.
foreign
____ keys work with primary keys to properly implement relationships in the relational model.
joining
____________________ a large number of tables takes additional input/output (I/O) operations and processing logic, thereby reducing system speed.
Attributes
____________________ are characteristics of entities.
Primary Keys
____________________ are underlined in an ER diagram.
Composite
____________________ attributes can be subdivided.
partial
____________________ completeness means some supertype occurrences that are not members of any subtype.
total
____________________ completeness means that every supertype occurrence must be a member of at least one subtype.
Data Inconsistency
____________________ exists when different and conflicting versions of the same data appear in different places.
Data Independence
____________________ exists when it is possible to make changes in the data storage characteristics without affecting the application program's ability to access the data.
Data Redundancy
____________________ exists when the same data are stored unnecessarily at different places.
Data Management
____________________ is a discipline that focuses on proper generation, storage and retrieval of data.
UML (Unified Modeling Language)
____________________ is a language based on OO concepts that describes a set of diagrams and symbols used to graphically model a system.
normalization
____________________ is a process to help reduce the likelihood of data anomalies
XML(Extensible Markup Language)
____________________ is a special language used to represent and manipulate data elements in a textual format.
Metadata
____________________ is data about data through which the end-user data are integrated and managed
JOIN
____________________ is the real power behind the relational database, allowing the use of independent tables linked by common attributes.
Outer
____________________ joins are especially useful when you are trying to determine what value(s) in related tables cause(s) referential integrity problems.
Granularity
____________________ refers to the level of detail represented by the values stored in a table's row.
M:N
____________________ relationships can be implemented by creating a new entity in 1:M relationships with the original entities.
reserved
____________________ words are words used by SQL to perform specific functions.
SELECT
____________________, coupled with appropriate search conditions, is an incredibly powerful tool that enables you to transform data into information.
Partial completeness is symbolized by ____.
a circle over a single line
Data quality
a comprehensive approach to promoting the accuracy, validity, and timeliness of the data.
Deadlock or deadly embrace
a condition that can occur during concurrent processing in which each of two or more transactions is waiting to access data that the other transaction has locked.
User defined data types
a data type that a user can define by making it a subclass of a standard type or creating a type that behaves as an object. UDTS may also have defined functions and methods.
Replicated database is
a database in which portions of the database are copied to two or more computers.
Partitioned database is
a database in which portions of the database are distributed to two or more computers
Distributed database is
a database that is stored and processed on two or more computers.
Business rules are derived from ____.
a detailed description of an organization's operations
System Catalog
a detailed system data dictionary that describes all objects within the database including data about table names, the table's creator and creation date, the number of columns in each table, the data type corresponding to each column, index filenames, index creators, authorized users, and access privileges
Data management
a discipline that focuses on the proper generation, storage, and retrieval of data. Given the crucial role that data play.
Log is
a file that contains a record of database changes. The log contains before-images and after-images.
Database Administration (DBA)
a function that concerns the effective use and control of a particular database and its related application.
Entity supertype
a generic entity type that is related to one or more entity subtypes
specialization hierarchy
a hierarchy that is based on the top-down process of identifying lower-level, more specific entity subtypes from a higher-level entity supertype. Specialization is based on grouping unique characteristics and relationships of the subtypes
Composite Key
a key that is made up of more than one attribute
Surrogate Key
a key we create to be a PK
Shared lock locks
a lock against a data resource in which only one transaction can update the data but many transactions can concurrently read those data.
Exclusive lock locks
a lock on a data resource that no other transaction can read or update
Optimistic locking
a locking strategy that assumes no conflict will occur, processes a transaction, and then checks to determine whether conflict did occur. If so, the transaction is aborted.
Pessimistic locking
a locking strategy that prevents conflict by placing locks before processing database read and write requests.
query language
a nonprocedural language—one that lets the user specify what must be done without having to specify how
surrogate key
a primary key created by the database designer to simplify the identification of entity instancs.
design trap
a problem that occurs when a relationship is improperly or incompletely identified and therefore is represented in a way that is not consistent with the real world.
Subquery
a query that is embedded(nested) inside another query - query nested in another query
Dirty Read is
a read of data that have been changed but not yet committed to a database. Such changes may later be rolled back and removed from the database. - Transaction 1 read a row changed by transaction 2 - Later transaction 2 cancels its change
natural key/identifier
a real world generally accepted identifier used to distinguish or uniquely identify real world objects
Natural Identifier
a real-world, generally accepted identifier used to identify real world objects. familiar to end users and forms part of their day-to-day vocabulary
After-image is
a record of a database entity after a change. Used in recovery to perform rollforward
Before-image is
a record of a database entity before a change. Used in recovery to perform rollback.
Dependency Diagram
a representation of all data dependencies (PK, Partial or Transitive) within a table - arrows on top are good dependencies - arrows on bottom are bad (partial & transitive)
Databases
a self-describing collection of related records, or, for relational databases, of related tables.
Transaction or Logical units of work (LUWs)
a series of actions to be taken on a database such that all of them are performed successfully or none of them are performed at all
An entity cluster is formed by combining multiple interrelated entities into ____.
a single abstract entity object
Nonrepeatable read is
a situation that occurs when a transaction reads data it has previously read and finds modifications or deletions caused by a committed transaction.
query
a specific request issued to the DBMS for data manipulation, predefined and routinely processed.
which of the following is an example of structured data? a. A Web page c. A memo b. An e-mail d. A spreadsheet
a spreadsheet
IN
a subquery can also return a list of values if it includes the keyword
Associative Entity (bridge entity, composite entity, or linking table)
a table used to link the tables that were originally a M:M relationship
MIN
aggregate function that yields the minimum attribute value encountered in a given column
2NF
all the key attributes are defined (no repeating groups in the table) , all remaining attributes are dependent on the primary key, and it includes no partial dependencies
1NF
all the key attributes are defined (no repeating groups in the table) and when all remaining attributes are dependent on the primary key
Hardware
all the system's physical devices
Key Attribute
an attribute that is part of a key
Keys
an attribute(s) we use to "determine" other attribute values
Data Administration
an enterprise wide function that concerns the effective use and control of an organization's data assets. A person can perform it but more often it is performed by a group. Specific functions include setting data standards and policies and providing a forum for conflict resolution.
____ is a generic entity type that is related to one or more entity subtypes.
an entity supertype
The lost update problem or concurrent update problem
an error condition in which one user's data changes are overwritten by another user's data changes.
A table that displays data redundancies yields ____.
anomalies
Determinant
any attribute in a specific determines other values in that row.
Super Key
any attribute or combination of attributes that will uniquely identify every row in the table
Primary Key
any candidate key that we select to be an identifier
rollback work
ask sql to empty the log file
TERNARY relationship
association between THREE entities
BINARY relationship
association between TWO entities - most common relationship
UNARY relationship
association within an entity (course is a pre-rec to another course)
ACID transaction is one that is
atomic, consistent, isolated, and durable.- atomic: happens as whole- durable: changes are permanent
A(n) ____ is the equivalent of a field in a file system.
attribute
In a relational table, each column has a specific range of values known as the ____________________ domain.
attribute
Foreign Key
attribute or combination of attributes in one table whose values must match the primary key i another (parent) table or whose values must be null
Non-Prime Attribute
attribute that is not part of a key
In the original ERM described by Chen, relationships do not contain ____________________.
attributes
In the specialization hierarchy there is a ____ relationship between a subtype and supertype.
b. 1:1
accurate, relevant, and timely information is the key to __ a. data management b. good decision making c. knowledge d. understanding
b. good decision making
_______relationships are most common
binary
A(n) ____________________ is a brief, precise, and unambiguous description of a policy, procedure, or principle within a specific organization.
business rule
>=ALL
can be used to match with the maximum value in a set
BCNF can be violated only if the table contains more than one ____ key.
candidate
An atomic attribute ____.
cannot be further subdivided
An automatic attribute__.
cannot be further subdivided
Repository
centralized storehouse of metadata
Structural independence
change file structure without affecting data access
Repeating Groups
characteristic describing a group of multiple entities of the same type that exist for a single key attribute occurrence. - repeating group = multivalued attribute
LEFT OUTER JOIN
clause causes customer data to appear even if there is no corresponding order data
Inner Join
clause is an alternative to WHERE clause, and is used to match primary and foreign keys
where
clause of the select command is also used for multiple table operations
ON
clause performs the equality check for common columns of the two tables
The relational operators have the property of ____________________; that is, the use of relational algebra operators on existing relations (tables) produces new relations.
closure
The database structure in a DBMS is stored as a ____.
collection of files
the database structure in a DBMS is stored as a __ a. file b. collection of files c. set of key/value pairs d. collection of queries
collection of files
Explicit locks are placed by
command
AUTOCOMMIT (ON/OFF)
command that specifies whether changes are made permanent after each data modification command or only when work is explicitly made permanent by the comit work command
transaction
complete set of closely related updated commands that must all done, or none of them done for the database to remain valid
The ____________________ constraint specifies whether each entity supertype occurrence must also be a member of at least one subtype.
completeness
A ____ attribute can be further subdivided to yield additional attributes.
composite
The associative entity is also known as a ____ entity.
composite
The conflicts between design efficiency and processing speed are often resolved through__
compromises that include denormalization
The conflicts between design efficiency, information requirements, and processing speed are often resolved through ____.
compromises that include renormalization
Case tools
computer-aided software engineering
Resource locking prevents
concurrent processing problems by disallowing sharing by locking data that are retrieved for update.
Transitive Dependency
condition where an attribute is dependent on another attribute that is not part of the primary key
A(n) ____ is a restriction placed on the data.
constraint
General-purpose databases
contain a wide variety of data used in multiple disciplines—for example, a census database that contains general demographic data
Discipline-specific databases
contain data focused on specific subject areas
____ are important because they help to ensure data integrity.
contraints
____ are normally expressed in the form of rules.
contraints
begin transaction
creates a log file and starts recording all changes (insertion, deletions and updates)
left outer join
customer_t was named first and this is the table we want the rows returned.
__ is used to reveal the meaning of data
d. information
A derived attribute is indicated in the Chen model by a ____
dashed line
Metadata
data about data, through which the end-user data are integrated and managed.
A(n) _______ develops when all required changes in the redundant data are not made successfully.
data anomaly
A(n) ____ enables a database administrator to define schema components.
data definition language (DDL)
A ____ contains at least all of the attribute names and characteristics for each table in the system.
data dictionary
Distributed database
data distributed across several sites
subquery
data from a ____ cannot be included in the final results
Information
data in context which is processed to reveal meaning. THE BEDROCK OF KNOWLEDGE
__ exists when different versions of the same data appear in different places a. Data inconsistency c. Better data integration b. Data consistency d. Improved decision making
data inconsistency
____________________ exists when different and conflicting versions of the same data appear in different places.
data inconstancy
____________________ exists when it is possible to make changes in the data storage characteristics without affecting the application program's ability to access the data.
data inpendence
Data redundancy produces __.
data integrity problems
Data redundancy produces ____.
data integrity problems
True
data is ubiquitous (abundant, global, everywhere) and pervasive (unescapable, prevalent, persistent)
Centralized database
data located at a single site
an_____ is a relatively simple representation of more complex real-world data structures.
data model
Information
data processed to increase knowledge in the person using the data
In early computer file systems, a(n) ___________________________________ was hired to create a computer-based system that would track data and produce required reports.
data processing specialist
Data independence
data storage characteristics do not affect data access
Metadata
data that describes the properties and context of user data.
Unstructured data
data that exist in their original (raw) state—that is, in the format in which they were collected
The ____ structure is quite different from that of an operational or transactional database.
data warehouse
the __ structure is quite different from that of an operational or transactional database a. data warehouse c. enterprise database b. workgroup database d. distributed database
data warehouse
time-variant data
data whose values are a function of time. For example, time variant data can be seen to work when the history of all administrative appointments(date of appointment and date of termination) are tracked. Implemented by creating a new entity with a 1:M relationship. Example manager and manager history
time-variant data
data whose values change over time and for which you must keep a history of the data changes. - requires a multivalued attribute which is resolved by creating a new table.
A(n) ___________________________________ is a collection of programs that manages the database structure and controls access to the data stored in the database.
database management system
the phrase __ refers to an organization of components that define and regulate the collection, storage, management and use of data within a database environment (a)database management system (c)management system (b)database management (d)database system
database system
In a __ diagram, the arrows above the attributes indicate all desirable dependencies.
dependency
specialization hierarchy
depicts the arrangement of higher-level entity supertypes (parent entities) and lower-level entity subtypes (child entities).
A(n) ____________________ attribute need not be physically stored within the database.
derived
From a strictly database point of view, ____ attribute values can be calculated when they are needed to write reports or invoices.
derived
business intelligence
describes a comprehensive approach to capture and process business data with the purpose of generating information to support business decision making.
CHEN
describes relationships (1:1, 1:M, and M;N) among entities at the conceptual level with the help of ER diagrams
Conceptual schema
designers and developers
maintenance and data integrity
designing a database so that data about about each object are kept in separate tables simplifies
A _________ is any attribute whose value determines other values within a column.
determinant
Attribute A __ attribute B if all of the rows in the table that agree in value for attribute A also agree in value for attribute B.
determines
a __ database supports data distributed across several different sites a. single-user c. centralized b. multiuser d. distributed
distributed
A(n) ____________________ is the attribute's set of possible values.
domain
OVERLAPPING subtypes
each entity instance of the supertype may appear in more than one subtype
TOTAL completeness
each instance of a super may appear in more than one subtype - overlapping subtype
UNION clause
each query must output the same number of columns to use the
inheritance
enables an entity subtype to inherit the attributes and relationships of the supertype.
The extended entity relationship model (EERM) is sometimes referred to as the ____.
enhanced entity relationship model
a(n) __ database is used by an organization and supports many users across many departments a. desktop c. enterprise b. workgroup d. transactional
enterprise
A relationship is an association between ____
entities
Normalization represents a micro view of the __ within the ERD.
entities
(n) ____ represents a particular type of object in the real world.
entity
A(n) ____ is anything about which data are to be collected and stored.
entity
The primary key's main function is to uniquely identify a(n) ____ within a table
entity instance or row
The ____ model was developed to allow designers to use a graphical tool to examine structures rather than describing them with text.
entity relationship
The ERM forms the basis of a(n) ____.
entity relationship diagram
The default comparison condition for the subtype discriminator attribute is the ____ comparison.
equality
CASE
establishing IF THEN ELSE logical processing within an sql statement can now be accomplished by using the ____ keyword
BCNF
every determinant in the table is a candidate key.
An entity is said to be ____-dependent if it can exist in the database only when it is associated with another related entity occurrence.
existence
In the relationship "EMPLOYEE claims DEPENDENT" the DEPENDENT entity is ____________________ on the EMPLOYEE entity.
existence-dependent
Partial Dependency
exists when an attribute is dependent on only a portion of the primary key.
The ____________________ is the result of adding more semantic constructs to the original entity relationship (ER) model
extended entity relationship model (EERM) extended entity relationship model
File system
extensive programming cannot perform ad hoc queries system administration is complex and difficult difficult to make changes to existing structures security features are likely to be inadequate
A foreign key must exist in both tables that have a relationship.
false
Atomic attributes are attributes that can be further divided.
false
Ideally, a primary key is composed of several attributes.
false
In specialization hierarchies with multiple levels of supertype/subtypes, a lower-level supertype inherits all of the attributes and relationships from all of its upper-level subtype.
false
Only a single attribute, not multiple attributes, can define functional dependence.
false
Relationships operate only in one direction.
false
Software vendors have adopted the Chen representation because of its compact representation
false
The Crow's Foot model is less implementation-oriented than the Chen model.
false
The existence of a mandatory relationship indicates that the minimum cardinality is 1 for the mandatory entity.
false
True or false A manager and a programmer usually have the same view of the same data.
false
True or false ... Business rules apply to businesses and government groups, but not to other types of organizations such as religious groups or research laboratories.
false
a query language is a procedural language
false
an operational database is sometimes referred to as an enterprise database
false
corporations use only structured data
false
data and information are essentially the same thing
false
database programming language receive all application requests and translate them into the complex operations required to fulfill those requests
false
implementating non-overlapping subtypes requires the use of one discriminator attribute for each subtype.
false
information implies familiarity, awareness, and understanding knowledge as it applies to an environment
false
one advantage of a database over previous data management approaches is that the database system is considerably less complex
false
one disadvantage of the DBMS is that it increases the risk of data security breaches
false
structural dependence exists when it is possible to make changes in the file structure without affecting the application program's ability to access the data
false
the DBMS reveals much of the database's internal complexity to the application programs and users
false
A ____ occurs when you have one entity in two 1:M relationships to other entities, thus producing an association among the other entities that is not expressed in the model.
fan trap
a __ is a character or group of characters that has a specific meaning (a)database (c)column (b)field (d)file
field
a __ is a collection of related records (a)database (c)column (b)field (d)file
file
To avoid nulls, some designers use special codes, known as ____________________, to indicate the absence of some value.
flags
In a real-world environment, we must strike a balance between design integrity and ____.
flexibility
analytical databases
focus primarily on storing historical data and business metrics used exclusively for tactical or strategic decision making
the proper use of ____________________ keys is crucial to controlling data redundancy.
foreign
Data must be properly _____ for storage, processing and presentation.
formatted
Raw data must be properly ____________________ for storage, processing and presentation.
formatted
Accurate, relevant, and timely information is the key to ____.
good decision making
____________________ refers to the level of detail represented by the values stored in a table's row.
granularity
Generalization
grouping of COMMON attributes into a SUPERtype entity
Specialization
grouping of UNIQUE attributes into a SUBtype entity
CASE
has four forms and can be constructed using the either an expression that equates to a value or predicate
In the ____ model, each parent can have many children, but each child has only one parent.
hierarchical
In the ____ model, the basic logical structure is represented as an upside-down tree.
hierarchical
One of the limitations of the ____ model is that there is a lack of standards.
hierarchical
physical data format
how the computer must work with the data
logical data format
how the human being views the data
Unstructured Data
images, video, documents
disjoint subtype
in a specialization hierarchy, a unique and nonoverlapping subtype entity set
full outer join
in this case all rows from both tables will be returned and matched, if possible including any rows that do not have a match in the other table
A(n) _________ is an orderly arrangement used to logically access rows in a table
index
The property of ____ enables an entity subtype to inherit the attributes and relationships of the supertype.
inheritance
the property of ____ enables an entity subtype to inherit the attributes and relationships of the supertype.
inheritance
Online analytical processing (OLAP)
is a set of tools that work together to provide an advanced data analysis environment for retrieving, processing, and modeling data from the data warehouse
Specialization
is a top-down process of identifying lower-level, more specific entity subtypes from a higher-level entity supertype. Example, identifying multiple entity subtypes from the original entity supertype
NATURAL
is an optional keyword
ad hoc query
is created to obtain information as the need arises
correlated subquery
is processed from the outside in
Generalization
is the bottom-up process of identifying a higher-level, more generic entity supertype from lower-level entity subtypes. Example, identifying a "string instrument" entity supertype from multiple instrument subtypes
distinct
is used when we do not care how many orders a customer has placed, as long as they have placed an order
Transaction is called atomic because
it it performed as a unit.
The organization of the data within the folders in a manual file system was determined by ____.
its expected use
the organization of the data within the folders in a manual file system was determined by __ a. the date of creation c.the title of the documents in the folder b.its expected used d.t he data processing specialist
its expected use
self join
joining a table with itself
same
joining and subqueries can sometimes produce the ___ results
Prime Attribute
key attribute that is part of a key or is the whole key. - prime attribute = if an attribute is part of the key
__ is the body of information and facts about a specific subject a. Data b. Information c. Knowledge d. A database
knowledge
correlated
like almost all other exists subqueries, is a _____ subquery
COUNT
lists total number of rows containing non-null values
When you can change the internal model without affecting the conceptual model, you have ____________________ independence.
logical
Codd's rule of ____ states: Application programs and ad hoc facilities are logically unaffected when changes are made to the table structures that preserve the original table values (changing order of columns or inserting columns).
logical data independence
When designing a database, you should__.
make sure entities are in normal for before table structures are created
When designing a database, you should ____.
make sure entities are in normal form before table structures are created
UPDATE
makes changes to data tables
Data ____ is a discipline that focuses on proper generation, storage and retrieval of data.
management
Data ____________________ is a discipline that focuses on proper generation, storage and retrieval of data.
management
A specialization hierarchy can have ____ level(s) of supertype/subtype relationships.
many
Students and classes have a ____ relationship.
many-to-many
begin transaction and end transaction
mark the boundaries of a logical unit of work
subquery
may only include one attribute
__ provide(s) a description of the data characteristics and the set of relationships that link the data found within the database a. Queries b. End-user data c. Metadata d. Information
metadata
Candidate Key
minimal number of attributes to identify every row
Candidate Key
minimal super-key, that is, one that does not contain a subset of attributes that is itself a supe-key
When indicating cardinality, the first value represents the ___ number of associated entities.
minimum
A(n) ____'s main function is to help you understand the complexities of the real-world environment.
model
CASE
more common applications are :1) to make up for SQL lack of enumerated <data type> 2) to perform if then calculations 3) for translations 4) to avoid expectations
A workgroup database is a(n)____ database.
multiuser
a workgroup database is a(n) __ database a. single-user c. enterprise b. multiuser d. distributed
multiuser
performance
n order to meet ___________________ requirements, you may have to denormalize some relations.
A ____ key is a real-world, generally accepted identifier used to distinguish that is, uniquely identify-real-world objects.
natural
A ____ key is a real-world, generally accepted identifier used to uniquely identify real-world objects.
natural
Surrogate primary keys are especially helpful when there is no ____ key.
natural
If one exists (and there are no security issues), a data modeler may use a ____ as the primary key of the entity being modeled.
natural identifier
If one exists, a data modeler uses a ____ as the primary key of the entity being modeled.
natural identifier
from
natural join is an optional key word when the join is defined in the ____ clause
A derived attribute ____.
need not be physically stored within the database
In the ____ model, the user perceives the database as a collection of records in 1:M relationships, where each record can have more than one parent.
network
The "____" characteristic of a primary key states that: The PK should not have embedded semantic meaning. An attribute with embedded semantic meaning is probably better used as a descriptive characteristic of the entity rather than as an identifier.
nonintelligent
____________________ is a process to help reduce the likelihood of data anomalies.
normalization
1NF, 2NF, and 3NF are__.
normalization stages
The WHERE clause
normally cannot include aggregate functions, but because the aggregate is performed in the subquery its result can be used in the outer query's WHERE clause.
PARTIAL completeness
not every supertype occurrence is a member of a subtype - a disjointed subtype
outer join
not null may be assigned as null in a ___
ERP - >100 users, GB-TB
ntegrate all enterprise functions (manufacturing, finance, sales, marketing, inventory, accounting, human resources)
All primary key entries are unique, and no part of a primary key may be ____
null
Ways Databases are Classified
number of users database locations expected type and extent of use
Structured Data
numbers, text , dates
The most likely data type for a surrogate key is ____.
numeric
The ____ model is said to be a semantic data model.
object-oriented
The ____ model uses the concept of inheritance.
object-oriented
Redundant relationships
occur when there are multiple (unnecessary) relationship paths between related entities.
Every subtype can have ____ supertype(s) to which it is directly related.
only one
Within a specialization hierarchy, every subtype can have ____ supertype(s) to which it is directly related.
only one
Natural join
only the 10 rows that have arrows drawn will be returned
Software
operating system, DBMS, and application programs and utility
Most decision-support data are based on historical data obtained from ____.
operational
a(n) __ database is designed to support a company's day-to-day operations a. desktop c. enterprise b. workgroup d. transactional
operational
most decision-support data are based on historical data obtained from __ a. operational databases c. enterprise databases b. data warehouses d. workgroup databases
operational databases
Participation is ____________________ if one entity occurrence does not require a corresponding entity occurrence in a particular relationship.
optional
Database
organized collection of logically related data
ORDER BY
organizes data
specialization hierarchy
organizes supertypes and subtypes. this depicts the arrangement of higher-level entity supertypes (parent entities) and lower-level entity subtypes (child entities).
Dependencies based on only a part of a composite primary key are called __ dependencies.
partial
Dependencies based on only a part of a composite primary key are called ____ dependencies.
partial
____________________ completeness means that not every supertype occurrence is a member of a subtype.
partial
If a table has multiple candidate keys and one of those candidate keys is a composite key, the table can have ____ based on this composite candidate key, even when the primary key chosen is a single attribute.
partial dependencies
A dependency based on only a part of a composite primary key is called a(n) ____________________.
partial dependency
__ relates to the activities that make the database perform more efficiently in terms of storage and access speed (a)Performance tuning (c)Query access (b)Database design (d)Database management
performance tuning
Internal schema
physical
The preferred placement for a foreign key when working with a 1:1 relationship is to ____.
place the foreign key in one of the entities
Subquery technique
placing an inner query ( select from where ) within a where or having clause of another (outer) query
Subquery-
placing an inner query (SELECT statement) inside an outer query
One important inheritance characteristic is that all entity subtypes inherit their ____ key attribute from their supertype.
primary
Since it is used to link the tables that originally were related in a M:N relationship, the composite entity structure includes—as foreign keys—at least the ____ keys of the tables that are to be linked.
primary
The most important characteristic of an entity is its ____ key, used to uniquely identify each entity instance
primary
An attribute that is part of a key is known as a __ attribute.
prime
An attribute that is part of a key is known as a(n) ____ attribute.
prime
Existence-Dependent
property of an entity whose existence depends on one more other entities.
Data Dictionary
provides a detailed description of all tables in the database created by the user and designer
WHERE
pulls data based on at least one attribute's specific value
FROM
pulls data from specified table
not exist
queries containing the keyword ____ will return a result table when no rows are found that satisfy the subquery
The response of the DBMS to a query is the ____.
query result set
the response of the DBMS to a query is the __ a. ad hoc query c. query result set b. ad hoc response d. integrated view of the data
query result set
End-user data is ____.
raw facts of interest to the end-user
end-user data is __ a. raw facts about the end-user b. raw facts of interest to the end-user c. data about data d. accurate, relevant and timely information
raw facts of interest to the end-user
Data
raw facts, building blocks of information
Natural Key
real world identifier used to uniquely ID real-world objects. Familiar to end users and forms part of their day-to-day business vocab
a __ is a logically connected set of one or more fields that describes a person, place, or thing (a) database (c) record (b)column (d)file
record
Recovery via rollback/rollforward
recovering a database by restoring the last full backup, and then using data stored in a transaction log to modify the database as needed by either adding transactions (rollforward) or removing erroneous transactions (rollback)
The Chen notation identifies the weak entity by using a double-walled entity ____.
rectangle
right outer join
referential integrity is being enforced
database system
refers to an organization of components that define and regulate the collection, storage, management, and use of data within a database environment
Database design
refers to the activities that focus on the design of the database structure that will be used to store and manage end-user data.
Performance tuning
relates to the activities that make the database perform more efficiently in terms of storage and access speed
The logical view of the relational database is facilitated by the creation of data relationships based on a logical construct known as a(n) ____________________.
relation
MySQL is an example of a(n) ____.
relational data model
A(n) ____________________ is a representation of the relational database's entities, the attributes within those entities and the relationships between those entities.
relational diagram
A ____ is a textual representation of the database tables where each table is listed by its name followed by the list of its attributes in parentheses.
relational schema
A verb associating two nouns in a business rule translates to a(n) ____ in the data model.
relationship
A(n) ____ is bidirectional.
relationship
According to the data modeling checklist, ____ should clearly define participation and cardinality rules.
relationships
DELETE
removes records (deletes a row from a table)
A ____ derives its name from the fact that a group of multiple entries of the same type can exist for any single key attribute occurrence.
repeating group
A relational table must not contain a __.
repeating group
A relational table must not contain a(n) ____.
repeating group
A(n) ____________________ derives its name from the fact that a group of multiple entries of the same type can exist for any single key attribute occurrence.
repeating group
Crow's Foot
representation of the entity relationship diagram using three-pronged symbol to represent the "many" sides of the relationship
Extensible Markup Language (XML)
represents data elements in textual format
extended entity relationship model (EERM)
result of adding more semantic constructs to the original entity relationship model
query result set
results of the query
catalog views
return info used by the SQL server database engine
SELECT
returns information from server
A __ lock locks a segment of the hard disk/volume hosting part of the database.
row-level
Data redundancy
same data stored unnecessarily in different places
The ____________________ is the conceptual organization of the entire database as viewed by the database administrator.
schema
A ____ key is defined as a key that is used strictly for data retrieval purposes.
secondary
The "____" characteristic of a primary key states that: The selected primary key must not be composed of any attribute(s) that might be considered a security risk or violation. For example, using a Social Security number as a PK in an EMPLOYEE table is not a good idea
security complaint
XML data is __ a. structured c. unstructured b. multistructured d. semistructured
semistructured
XML data is ____
semistructured
most data you encounter is best classified as __ a. structured c. unstructured b. semistructured d. historical
semistructured
Manual file systems
served as a data repository for small data collections. Cumbersome for large collections
SQL
set oriented language
Database
shared, integrated computer structure that stores a collection of end-user data and metadata.
Homonyms
similar-sounding words with different meanings, or a word that with different meanings Ex. Boar and Bore Fair (just & festival)
A desktop database is a ____ database.
single-user
a desktop database is a __ database a. single-user c. workgroup b. multiuser d. distributed
single-user
DBMS
software for managing the database
Application programs
software using the data
The ____ depicts the arrangement of higher-level entity supertypes (parent entities) and lower-level entity subtypes (child entities).
specialization hierarchy
The relationships depicted within the ____ are sometimes described in terms of "is-a" relationships.
specialization hierarchy
two
sql has __ ways to use select for combining data from related tables
Data
stored representations of meaningful objects and events.
Database
storehouse of the data
Data warehouse
stores data used for tactical or strategic decisions
__ data are the result of formatting to facilitate storage, use and generation of information a. Structured c. Unstructured b. Semistructured d. Historical
structured
___ data are the result of formatting to facilitate storage, use and generation of information.
structured
set-oriented language
subqueries are a prime example of why SQL is a
nested queries
subqueries are also called
where
subqueries are not limited to _____ clause but from clause to create a temporary derived table
The ____________________ defines the portion of the database "seen" by the application programs that produce information from the data.
subschema
A(n) ____ is the attribute in the supertype entity that determines to which entity subtype each supertype occurrence is related.
subtype discriminator
Overlapping subtypes are subtypes that contain ____ subsets of the supertype entity set.
subtypes
disjoint constraints
subtypes that are unique. Example a pilot is a unique type of employee. Shown as a closed circle with a (d)
overlapping constraints
subtypes that contain nonunique subsets of the supertype entity set. Example student and employee or both. Shown as a closed circle with an (o)
Operational database
supports a company's day-to-day operations also known as an online transaction processing (OLTP), transactional, or production database
Multi-user database (workgroup database)
supports multiple users at the same time (workgroup and enterprise)
Single-user database (desktop database)
supports only one user at a time (desktop)
outer join
syntax do not easily apply to a join condition of more than two tables
The ____________________ catalog can be described as a detailed system data dictionary that describes all objects within the database, including data about table names, the table's creator and creation date, the number of columns in each table, the data type corresponding to each column, index filenames, index creators, authorized users, and access privileges.
system
compatibility views
system tables from earlier release of SQL server
the relational model's creator, E. F. Codd, used the term relation as a synonym for ____.
table
result or answer table
table created by the query is called the
end transaction or commit work
takes the contents of the log file and applied them to the database, thus making the changes permanent and then empties the log file
An example of denormalization is using a ____ denormalized table to hold report data. This is required when creating a tabular report in which the columns represent data that is stored in the table as rows.
temporary
A ____ relationship exists when three entities are associated
tenary
subtype discriminator
the attribute in the supertype entity that determines to which entity subtype each supertype occurrence is related.
Subtype DISCRIMINATOR
the attribute in the supertype entity that is used to determine to which entity subtype the supertype occurrence is related
generalization
the bottom-up process of identifying a higher level, more generic entity supertype from lower-level entity subtypes
Attribute Domain
the construct used to organize and describe an attribute's set of possible values
entity subtype
the entity supertype contains common characteristics and the entity subtypes contain unique characteristics of each entity subtype. Example employee and pilot
DBMS
the intermediary between the user and the database
Granularity refers to __.
the level of detain represented by the values stored in a tables row
Transactions are interleaved means
the operating system switches cpu services among tasks
Synonyms
the opposite of a homonym, and indicates the use of different names to describe the same attribute
Foreign Key
the primary key of one table used to establish a relationship with instances of a second table
Normalization
the process for evaluating and correcting table structures to - minimize data redundancies - reduce likelihood of data anomalies - minimize and/or eliminate data integrity problems
Structured data
the result of formatting unstructured data to facilitate storage, use, and the generation of information
Determination
the state in which knowing the value of one attribute makes it possible to determine the value of another
specialization
the top-down process of identifying lower-level, more specific entity subtypes from a higher-level entity supertype
Functional Dependence
the value of one or more attributes determines the value of one or more other attributes Ex. Invoice # - Products/Customer CustomerID - Last Name/First Name Banner ID - Last Name/First Name
overlapping subtype
these contain nonunique subsets of the supertype entity set; that is, each entity instance of the supertype may appear in more than one subtype.
subtype discriminator
this is the attribute in the supertype entity that determines to which subtype the supertype occurence is related.
total completeness
this means that every supertype ocurence must be a member of at least one subtype
fan trap
this occurs when you have one entity in two 1:M relationships to other entities, thus producing an association among the other entities that is not expressed in the model.
time-variant data
this refers to data whose values change over time and for which you must keep a history of the data changes
partial completeness
this specifies whether each entity supertype occurence must also be a member of at least one subtype.
=
to be safe, use the IN operator than ___ when writing queries
derived table
to display both average standard price and standard price the ______ is used
INTERSECT
to find the elements in common between two sets
MINUS
to find the elements in one set that are not in another set
join technique
to include data from subquery_____ is used
A(n) ____ database is designed to support a company's day-to-day operations
transactional
A __ exists when there are functional dependencies such that Y is a functional dependent on X and Z is functional dependent on Y, and X is the primary key.
transitive dependency
A ____ exists when there are functional dependencies such that Y is functionally dependent on X and Z is functionally dependent on Y, and X is the primary key.
transitive dependency
A(n) ____ exists when there are functional dependencies such that Y is functionally dependent on X and Z is functionally dependent on Y, and X is the primary key.
transitive dependency
A composite identifier is a primary key composed of more than one attribute.
true
A null is created when you press the Enter key or the Tab key to move to the next entry without making a prior entry of any kind.
true
As rare as 1:1 relationships should be, certain conditions absolutely require their use.
true
It is possible for a table in 2NF to exhibit transitive dependency, where one or more nonprime attributes functionally determine other nonprime attributes.
true
Some designs use redundant relationships as a way to simplify the design.
true
The entity supertype contains the common characteristics and the entity subtypes contain the unique characteristics of each entity subtype.
true
The practical significance of taking the logical view of a database is that it serves as a reminder of the simple file concept of data storage.
true
a data warehouse can store data derived from many sources
true
data constitute the building blocks of information
true
data processing can be as simple as organizing data to reveal patterns
true
historically, a manual file system was composed of a system of file folders and filing cabinets
true
initially the files within a computer file system were similar to manual files
true
metadata present a more complete picture of the data in the database than the data itself
true
one disadvantage of a database system over previous data management approaches is increased costs
true
the only way to access the data in the database is through the DBMS
true
the same data might be simultaneously structured and unstructured depending on the intended processing
true
true or false....M:N relationships are not appropriate in a relational model.
true
we are now said to be entering the "knowledge age"
true
with partial dependencies, data redundancies occur because every row entry requires duplication of data.
true
In an ER diagram, primary keys are indicated by ____.
underlining
better design query
understand how indexes are used in query processing keep optimizer statistics up to date use compatible data types for fields and literal in queries write simple queries break complex queries into multiple simple parts dont nest one query inside another query dont combine a table with itself create temporary tables for groups of queries combine update operations retrieve only the data you need dont have the DBMS sort without an index learn! consider the total query processing time for ad hoc queries
outer join
union and not exists can be used in place of
A(n) ____________________ index is an index in which the index key can have only one pointer value (row) associated with it.
unique
Non-overlapping subtypes are subtypes that contain a(n) ____ subset of the supertype entity set.
unique
The "____" characteristic of a primary key states that: The PK must uniquely identify each entity instance. A primary key must be able to guarantee unique values. It cannot contain nulls.
unique values
__ data exist in a format that does not lend itself to processing that yields information a. Structured c. Unstructured b. Semistructured d. Historical
unstructured
__ data exist in the format in which they were collected a. Structured c. Unstructured b. Semistructured d. Historical
unstructured
The most common anomalies considered when data redundancy exists are:
update, insertion, deletion anomalies
