Final Exam Set
Which of the following are properties of relations?
1. Each attribute has a unique name 2.No two rows in a relation are identical 3.There are no multivalued attributes in a relation
A factor to consider when choosing a file organization is
1. Fast data retrieval 2. security 3. efficient storage
Main goals of Normalization
1. minimize data redundancy 2. simplify the enforcement of referential integrity 3.make it easier to maintain data
All of the following are common denormalization opportunities EXCEPT
A one-to-many relationship
What does the following SQL command do? insert into Customer_T values (001,'John Smith','231 West St','Boston','MA','02115');
Adds a new record to the Customer_T table
The SQL command ________ adds one or more new columns to a table.
Alter Table
Alters the Customer_T table, and adds a field called "Type"What does the following SQL statement do? Alter Table Customer_T Add (Type Varchar (2));
Alters the Customer_T table, and adds a field called "Type"
All of the following are valid datatypes in Oracle 11g EXCEPT
Boolean
What does the following SQL statement do? Update Product_T Set Unit_Price = 775 Where Product_ID = 7
Changes the unit price of Product 7 to 775
Sensitivity testing involves
Checking to see if missing data will greatly impact results
Which of the following is a technique for optimizing the internal performance of the relational data model?
Clustering Data
The SQL command ________ defines a logical table from one or more tables or views
Create View
________ is a set of commands used to control a database, which includes security
DCL
________ is a set of commands used to update and query a database
DML
Physical database design decisions must be made carefully because of impacts on
Data Accessibility, Response Time & Security
Anomalies do not generally arise out of transitive dependencies
False
The purpose of data modeling is to document business rules about processes
False
The term legacy system refers to a newly installed database management system.
False
Which of the following is an objective of selecting a data type
Improve Data Integrity
A domain definition consists of the following components EXCEPT
Integrity Constraints
The benefits of a standardized relational language include:
The benefits of a standardized relational language include:-application longevity -reduced training costs -cross system communication
Database access frequencies are estimated from
Transaction Volumes
A cascading delete removes all records in other tables associated with the record to be deleted
True
A data model is a graphical system used to capture the nature and relationships among data.
True
A fact is an association between two or more terms
True
A partial functional dependency is a functional dependency in which one or more nonkey attributes are functionally dependent on part (but not all) of the primary key.
True
A person is an example of an entity.
True
A range control limits the set of permissible values that a field may assume
True
A referential integrity constraint is a rule that maintains consistency among the rows of two relations
True
A relational database establishes the relationships between entities by means of a common field.
True
A single occurrence of an entity is called an entity instance.
True
Keeping the zip code with the city and state in a table is a typical form of denormalization
True
Many of the disadvantages of file processing systems can also be limitations of databases
True
One of the roles of a database analyst is to identify and understand rules that govern data
True
When choosing an identifier, choose one that will not change its value often
True
While business rules are not redundant, a business rule can refer to another business rule.
True
Given a table named store with 5 fields: store_id, address, city, state, zipcode, why would the following insert command not work? insert into store values ('234 Park Street')
You must specify the fields to insert if you are only inserting some of the fields
Which of the following is NOT an advantage of database systems?
elimination of data redundancy, ability of associate deleted data, increased security, program/data independence
Customers, cars, and parts are examples of:
entities
Which of the following is an entity that exists independently of other entity types?
strong
The most common types of entities are:
strong entities
A fact is an association between two or more
terms
A simultaneous relationship among the instances of three entity types is called a ________ relationship.
ternary
Which organizational function should set database standards?
the database administrator
Which of the following is NOT an objective that drove the development and evolution of database technology?
the desire to require programmers to write all file handling functionality
All values that appear in a column of a relation must be taken from the same domain
True
One of the most popular RAD methods is:
prototyping
A workgroup database is stored on a central device called a:
server
The value a field will assume unless the user enters an explicit value for an instance of that field is called a(n):
Default Value
The intent of a business rule is to break down business structure
False
When all multivalued attributes have been removed from a relation, it is said to be in
First Normal Form
Distributing the rows of data into separate files is called
Horizontal Partitioning
The first in a series of steps to follow when creating a table is to
Identify each attribute and its characteristics
The three-schema approach includes which of the following schemas?
Internal, conceptual or external
E. F. Codd developed the relational model in the:
1970's for IBM
A well-structured database establishes the entities between relationships in order to derive the desired information.
False
An entity type on which a strong entity is dependent is called a covariant entity.
False
An example of a term would be the following sentence: "A student registers for a course."
False
Indexes are most useful on small, clustered files
False
Most systems developers believe that data modeling is the least important part of the systems development process.
False
Organizational commitment to a database project is not necessary for its success
False
A functional dependency between two or more nonkey attributes is called a
Transitive Dependency
The number of entity types that participate in a relationship is called the:
degree
A centralized knowledge base of all data definitions, data relationships, screen and report formats, and other system components is called a(n):
repository
A knowledge base of information or facts about an enterprise is called a(n):
repository
With the database approach, data descriptions are stored in a central location known as a:
repository
An attribute of an entity that must have a value for each entity instance is a(n):
required attribute
An attribute that must have a value for every entity (or relationship) instance is a(n):
required attribute
A requirement to begin designing physical files and databases is
1. normalized relations 2. definitions of each attribute 3. technology descriptions
A method for handling missing data is to
1. substitute and estimate for the missing data 2. track missing data with special reports 3. perform sensitivity testing
A candidate key must satisfy all of the following conditions
1. the key must uniquely identify the row 2. the key must be nonredundant 3. each nonkey attribute is functionally dependent upon it
________ is a component of the relational data model included to specify business rules to maintain the integrity of data when they are manipulated.
Data Integrity
The relational data model consists of which components?
Data Structure, Data Manipulation & Data Integrity
Deletes all records from customer_t where the state is equal to HIWhat does the following SQL statement do? Delete from Customer_T where state = 'HI';
Deletes all records from customer_t where the state is equal to HI
The attribute on the left-hand side of the arrow in a functional dependency is the
Determinant
Any create command may be reversed by using a ________ command
Drop
An advantage of partitioning is
Efficiency
The ________ states that no primary key attribute may be null
Entity Integrity Rule
A business rule is a statement of how a policy is enforced or conducted.
False
A constraint is a rule in a database system that can be violated by users.
False
A file organization is a named portion of primary memory
False
A key is a data structure used to determine the location of rows in a file that satisfy some condition
False
A relation is in first normal form if it has no more than one multivalued attribute
False
A transversal dependency is a functional dependency between two or more nonkey attributes
False
A user view is how the user sees the data when it is produced.
False
An anomaly is a type of flaw in the database server
False
Business rules are formulated from a collection of business ramblings.
False
Data names do not have to be unique.
False
Data redundancy is used to establish relationships between data but is never used to improve database performance
False
Databases were developed as the first application of computers to data processing
False
Denormalization is the process of transforming relations with variable-length fields into those with fixed-length fields
False
In an E-R diagram, strong entities are represented by double-walled rectangles
False
In the relational data model, associations between tables are defined through the use of primary keys
False
Organizations that utilize the file processing approach spend only 20 percent of development time on maintenance
False
Personal databases are designed to support a small group of individuals working together on a project.
False
Reduced program maintenance is an advantage of file processing systems.
False
Reduced uptime is a disadvantage of partitioning.
False
Repositories are always used in file processing systems.
False
Some examples of attributes are: eye_color, weight, student_id, STUDENT.
False
The data that you are interested in capturing about an entity is called an instance.
False
The entity integrity rule states that a primary key attribute can be null
False
The name used for an entity type should never be the same in other E-R diagrams on which the entity appears
False
Unlike columns, the rows of a relation may not be interchanged and must be stored in one sequence
False
When systems are automatically generated and maintained, quality is diminished
False
When transforming a one-to-one relationship, a new relation is always created
False
When transforming a unary many-to-many relationship to relations, a recursive foreign key is used
False
When transforming a weak entity, one should create one relation with both the attributes of the strong entity and the attributes of the weak entity
False
With the traditional file processing approach, each application shares data files, thus enabling much data sharing.
False
The smallest unit of application data recognized by system software is a
Field
Which of the following is NOT a cost and/or risk of the database approach?
Improved responsiveness
A form of database specification that indicates all the parameters for data storage that are then input to database implementation is
Physical
DDL is typically used during which phases of the development process?
Physical Design
A(n) ________ is a field of data used to locate a related field or record
Pointer
Purpose of the SQL standard
Purpose of the SQL standard-To specify syntax and semantics of SQL data definition and manipulation -To specify minimal and complete standards, which permit different degrees of adoption in products -To define the data structures and basic operations for SQL databases
An integrity control supported by a DBMS is
Range Control
A rule that states that each foreign key value must match a primary key value in the other relation is called the
Referential Integrity Constraint
The traditional methodology used to develop, maintain and replace information systems is called the:
SDLC ( systems development life cycle)
The ________ is the structure that contains descriptions of objects such as tables and views created by users
Schema
A relation that contains no multivalued attributes and has nonkey attributes solely dependent on the primary key but contains transitive dependencies is in which normal form?
Second Normal Form
A business rule is a statement that defines or constrains some aspect of the business.
True
A business rule should be internally consistent.
True
A candidate key is an attribute, or combination of attributes, that uniquely identifies a row in a relation
True
A foreign key is a primary key of a relation that also is a primary key in another relation.
True
A good data definition is always accompanied by diagrams, such as the entity-relationship diagram.
True
A modern database management system automates more of the backup and recovery tasks than a file system.
True
A well-structured relation contains minimal redundancy and allows users to manipulate the relation without errors or inconsistencies.
True
An entity is a person, place, object, event, or concept in the user environment about which the organization wishes to maintain data.
True
An entity type name should always be a singular noun.
True
Clustering allows for adjacent secondary memory locations to contain rows from several tables.
True
Cost and complexity are just two of the disadvantages of database processing
True
Data modeling is about documenting rules and policies of an organization that govern data.
True
Data names should always relate to business characteristics.
True
Data, rather than processes, are the most complex aspects of many modern information systems.
True
Development starts from scratch with the traditional file processing approach because new file formats, descriptions, and file access logic must be designed for each new program.
True
Enforcement of business rules can be automated through the use of software tools that can interpret the rules and enforce them.
True
File processing systems have been replaced by database systems in most critical business applications today.
True
If an identifier is not assigned, the default primary key for an associative relation consists of the two primary key attributes from the other two relations.
True
In an E-R diagram, an associative entity is represented by a rounded rectangle
True
Information is processed data.
True
One reason for improved application development productivity with the database approach is that file design and low-level implementation details do not need to be handled by the application programmer.
True
Redundancy increases the risk of inconsistent data
True
Security is one advantage of partitioning
True
Separation of metadata from application programs that use the data is called data independence.
True
The E-R model is used to construct a conceptual model.
True
The allowable range of values for a given attribute is part of the domain constraint
True
The columns of a relation can be interchanged without changing the meaning or use of the relation
True
The data repository assists database administrators in enforcing standards.
True
The failure to implement a strong database administrative function is the most common source of database failures in organizations.
True
The relationship between a weak entity type and its owner is an identifying relationship.
True
The user interface includes languages, menus, and other facilities by which users interact with various system components
True
Unplanned duplicate data files are the rule rather than the exception in file processing systems.
True
When normalizing, the goal is to decompose relations with anomalies to produce smaller, well-structured relations
True
A user view is:
a view of part or all of the contents of a database specified for specific user activity
The SDLC phase in which the detailed conceptual data model is created is the ________ phase.
analysis
In a file processing environment, descriptions for data and the logic for accessing the data are built into:
application programs
An entity type name should be all of the following EXCEPT:
as short as possible
A property or characteristic of an entity type that is of interest to the organization is called a(n):
attribute
A person's name, birthday, and social security number are all examples of:
attributes
Data that describe the properties of other data are:
attributes
A ________ defines or constrains some aspect of the business.
business rule
An attribute that can be broken down into smaller parts is called a(n) ________ attribute.
composite
A rule that CANNOT be violated by database users is called a:
constraint
The command for creating a database is
create table
Data modeling may be the most important part of the systems development process because:
data characteristics are important in the design of programs and other systems components.
. A graphical system used to capture the nature and relationships among data is called a(n):
data model
. Database development begins with ________, which establishes the range and general contents of organizational databases.
enterprise data modeling
A person, place, object, event, or concept about which the organization wishes to maintain
entity
The logical representation of an organization's data is called a(n):
entity- relationship model
The most common source of database failures in organizations is:
failure to implement strong database administrator functions
3. Program-data dependence is caused by:
file processing
A(n) ________ is the relationship between a weak entity type and its owner.
identifying relationship
Which of the following is NOT a characteristic of a good business rule?
inconsistent
Purpose of creating indexes?
increases speed or row selection, table joining, and row ordering
2. Older systems that often contain data of poor quality are called ________ systems
legacy
1. A database is an organized collection of ________ related data.
logically
Business policies and rules govern all of the following EXCEPT:
managing employees
The entity integrity rule states that
no primary key attribute can be null
The number of entity types that participate in a Unary relationship is:
one
While Oracle has responsibility for managing data inside a tablespace, the tablespace as a whole is managed by the
operating system
All of the following are properties of metadata EXCEPT
processing logic
All of the following are primary purposes of a database management system (DBMS) EXCEPT:
providing an integrated work environment
Which of the following is NOT a good characteristic of a data name?
relates to technical characteristics of the system
Relational databases establish the relationships between entities by means of common fields included in a file called a(n):
relation
________ are established between entities in a well-structured database so that the desired information can be retrieved.
relationships
In an E-R diagram, there are/is ________ business rule(s) for every relationship.
two
A relationship between the instances of a single entity type is called a ________ relationship.
unary
4. Because applications are often developed independently in file processing systems:
unplanned duplicate data files are the rule rather than the exception
All of the following are objectives when selecting a data type EXCEPT
use a lot of storage space
A(n) ________ is often developed by identifying a form or report that a user needs on a regular basis
user review
An entity type whose existence depends on another entity type is called a ________ entity.
weak
Horizontal partitioning makes sense when
when different categories of a table's rows are processed separately
A good data definition will describe all of the characteristics of a data object EXCEPT:
who can delete the data
.Understanding the steps involved in transforming EER diagrams into relations is important because
you must be able to check the output of a CASE tool