Database Systems
The hierarchical database model depicts a set of ____ relationships
1:M
Which of the following statements concerning the primary key is true?
All primary key entries are unique.
Numeric data are data on which you can perform meaningful ____________________ procedures
Arithmetic
In a sophisticated application development software, nulls can create problems when using functions such as:
COUNT, SUM, and AVERAGE
A primary key that consists of more than one field is called a ____ key
Composite
A key that consists of more than one field is called a ____.
Composite key
The ____ model presents a global view of the database
Conceptual
The key's role is based on a concept known as ____.
Determination
The key's role is based on a concept known as ____________________.
Determination
In response to the increasing complexity of applications, two new data models emerged: the object-oriented data model and the ____ relational data model.
Extended
Which model represents the end user's view of the database?
External
(T/F) A data model is built out of tables, rows, and columns.
False
(T/F) A primary key can be defined as a superkey with redundancies
False
(T/F) A(n) fourth-generation programming language requires the programmer to specify both what must be done and how it is to be done
False
(T/F) Character data can contain any character or symbol intended for mathematical manipulation
False
(T/F) Data consistency exists when different and conflicting versions of the same data appear in different places
False
(T/F) Data modeling is usually skipped due to time constraints
False
(T/F) Each column in a relational table has a specific range of values knows as the attribute object
False
(T/F) Having fields stored in one location produces data redundancy
False
(T/F) Hierarchal databases became popular in the 1980s
False
(T/F) In 1975, it was decided that all databases should conform to the SPARC standard
False
(T/F) In a relational table, each table row (tuple) does not necessarily represent a single entity occurrence within the entry set.
False
(T/F) In an inner JOIN, the matched pairs would be retained and any unmatched values in the other table would be left null.
False
(T/F) In the network model, it is possible for a member to exist without an owner.
False
(T/F) Many-to-many relationships are easily represented using a hierarchical model.
False
(T/F) Only 1:M and M:N relationships can be represented in a relational schema.
False
(T/F) The developer of the relational model worked for Microsoft
False
(T/F) The hierarchical model was the first to define a standard DML and DDL
False
(T/F) The top layer of the hierarchical model is known as the treetop
False
(T/F) To maintain entity integrity, a null value is permitted in the primary key.
False
(T/F)When two or more tables share the same columns and domains, they are said to be incompatible
False
In a relational table, each row/column ____________________ represents a single data value
Intersection
The final outcome of a natural ____________________ yields a table that does not include unmatched pairs
JOIN
Date attributes contain calendar dates stored in a special format known as ____________________ date format
Julian
What type of relationship is expressed with the phrase "Student takes Class"?
M:N
The short Date format is ____.
MM/DD/YY
Which of the following database models is NOT still in use today?
Network
Which of the following databases does NOT provide structural independence?
Network
Data are classified, according to their format and function, into which categories?
Numeric, character, date, and logical
Which of the following data models contains the most semantics?
Object-oriented
In network model terminology, each set is composed of a(n) ____________________ and a member
Owner
Which of the following is not a degree of abstraction as defined by ANSI/SPARC?
Physical
In general terms, the ____ key is an attribute (or combination of attributes) that uniquely identifies any given entity.
Primary
The ____________________ model is to database design what the automatic transmission is to cars.
Relational
A relational operator that yields values from all rows in a table is known as the ____ operator
SELECT
In 1975, the ANSI __________ augmented the network model database standards
SPARC
The query language for a relational database is _________________________.
Structured Query Language
A ____________________ is perceived as a two-dimensional structure composed of rows and columns.
Table
(T/F) A column's range of permissible values is known as its domain
True
(T/F) A key consists of one or more attributes that determine other attributes.
True
(T/F) A matrix consisting of a series of a row and column intersection is a table
True
(T/F) A natural JOIN links tables by selecting only the rows with common values in their common attribute(s).
True
(T/F) A segment is the equivalent of a file system's record type.
True
(T/F) An entity is a person, place, or thing about which data are to be collected and stored
True
(T/F) An entity set is a named collection of entities that share common characteristics
True
(T/F) Another form of JOIN, known as equijoin, links tables on the basis of an equality condition that compares specified columns of each table.
True
(T/F) Business rules help you determine the relationships that exist between entities.
True
(T/F) Date attributes contain calendar dates stored in a special format known as Julian date format
True
(T/F) Each entity has certain characteristics known as attributes
True
(T/F) Each segment in a hierarchical structure is referenced by a path
True
(T/F) In a relational table, each column represents an attribute and each column has a distinctive name
True
(T/F) In a relational table, each table must have an attribute or a combination of attributes that uniquely identifies each row.
True
(T/F) In network database terminology, 1:M relationships are represented using a database table
True
(T/F) In the network model, an entity can have more than one owner
True
(T/F) Logical data can have only a true or false (yes or no) condition.
True
(T/F) Numeric data are data on which you can perform meaningful arithmetic procedures.
True
(T/F) Outer joins are especially useful when trying to determine what values in related table(s) cause referential integrity problems
True
(T/F) Relations are related to each other by sharing a common entity characteristic
True
(T/F) SQL makes pure ad hoc queries a reality.
True
(T/F) The DBTG report contained specifications for a schema and subschema
True
(T/F) The proper use of foreign keys is crucial to exercising data redundancy control.
True
A relational operator that combines all rows from two tables is considered to be a(n) ____.
UNION
Nulls, if used improperly, can create problems because they can represent ____.
a known, but missing, attribute value
We can describe a link by observing that ____.
a primary key of one table appears again as a foreign key in a related table
The OODM _____
adds semantic content
The entity integrity rule requires that ____.
all primary key entries are unique
Each table column represents a(n) ____________________ and has a distinct name
attribute
Metadata is:
data about data
The DBMS stores definitions of the data elements and their relationships in a
data dictionary
Because an RDBMS hides the system's complexity from the user/designer, ____.
data management is easier
A ____________________ focuses primarily on storing data used to generate information required to make tactical or strategic decisions
data warehouse
One of the advantages of a relational database model is ____.
easier database design
A(n) ____________________ is a person, place, or thing about which information is stored.
entity
The referential integrity rule requires that ____.
every non-null foreign key value reference an existing primary key value
An attribute (or combination of attributes) in one table whose values must either match the primary key in another table or be null is called a ____ key.
foreign
The ____________________ database is a collection of records that is logically organized to conform with the upside-down tree
hierarchical
A table is a matrix consisting of a series of row and column ____.
intersections
A(n) ____________________ consists of one or more attributes that determine other attributes
key
The ____________________ view of a relational database is facilitated by the creation of data relationships based on a construct known as a table
logical
Database models were developed to ____.
model real-world events or conditions
The ____________________ model was created to represent complex data relationships more effectively than the hierarchical model could and to impose a database standard
network
The RDBMS
performs functions provided by the hierarchical and network DBMS system
A null value is created or represented by ____.
pressing the Enter key without making a prior entry of any kind
The hierarchical database models ____.
promote database integrity
A data model must represent the ____ world as closely as possible
real
If a foreign key contains either matching values or nulls, the table(s) that make use of such a foreign key is/are said to exhibit ____ integrity
referential
The network ____________________ is the conceptual organization of the entire database as viewed by the database administrator
schema
In network database terminology, a relationship is called a(n) ____________
set
A(n) ____________________ is a matrix consisting of a series of row/column intersections.
table
A relational database is a group of ____.
tables
