Exam 1 Multiple Choice 2

____ yields only the rows that appear in both tables.

INTERSECT

____ data can have only a true or false (yes or no) condition.

Logical

____ yields a vertical subset of a table.

PROJECT

____ key is a minimal (irreducible) superkey.

candidate

The ____ model was developed to allow designers to use a graphical tool to examine structures rather than describing them with

entity relationship

VMS/VSAM is an example of a(n) ____.

file system data model

One of the limitations of the ____ model was that there were no implementation standards.

hierarchical

Referential ____ means that if the foreign key contains a value, that value refers to an existing valid tuple (row) in another relation.

integrity

The relational database model enables you to view data ____ rather than ____.

logically,physically

A(n) ____ join links tables by selecting only the rows with common values in their common attribute(s).

natural

All primary key entries are unique, and no part of a primary key may be ____.

null

In an outer join, the matched pairs would be retained and any unmatched values in the other table would be left ____.

null

No data entry at all is known as a(n) ____.

null

The ____ model is said to be a semantic data model.

object-oriented

The ____ model uses the concept of inheritance.

object-oriented

A ____ key is defined as a key that is used strictly for data retrieval purposes.

secondary

The equijoin takes its name from the comparison operator ____ used in the condition.

=

The DBTG report contains specifications for a(n) ____ that defines the environment in which data is to be managed.

DML

Which data model has the highest level of abstraction?

Entity relationship

Date attributes contain calendar dates stored in a special format known as the ____ date format.

Julian

The ____ constraint can be placed on a column to ensure that every row in the table has a value for that column.

NOT NULL

In the following table description, ____ is the primary key.

PROD_CODE

____ logic, used extensively in mathematics, provides a framework in which an assertion (statement of fact) can be verified as either

Predicate

To be considered minimally relational, the DBMS must support the key relational operators ____, PROJECT, and JOIN.

SELECT

____, also known as RESTRICT, yields values for all rows found in a table that satisfy a given condition.

SELECT

____ combines all rows from two tables, excluding duplicate rows.

UNION

Oracle 10g is an example of a(n) ____.

XML data model

If the attribute (B) is functionally dependent on a composite key (A) but not on any subset of that ____ key, the attribute (B) is fully functionally dependent on (A).

composite

The ____ model represents a global view of the database as viewed by the entire organization.

conceptual

A ____ contains at least all of the attribute names and characteristics for each table in the system.

data dictionary

In the context of a database table, the statement "A ____ B" indicates that if you know the value of attribute A, you can look up the

determines

A CUSTOMER table's primary key is CUS_CODE. The CUSTOMER primary key column has no null entries, and all entries are unique. This is an example of ____ integrity.

entity

The ____ model uses the term connectivity to label the relationship types.

entity relationship

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

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

Any attribute that is part of a key is known as a ____.

key attribute

In the relational model, ____ are important because they are used to ensure that each row in a table is uniquely identifiable

keys

In the ____ model, the user perceives the database as a collection of records in 1:M relationships, where each record can have more

network

Controlled ____ makes a relational database work

redundancy

MySQL is an example of a(n) ____.

relational data model

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

relational schema

A ____ is any key that uniquely identifies each row.

superkey

A(n) ____ is perceived as a two-dimensional structure composed of rows and columns.

table

The relational model's creator, E. F. Codd, used the term relation as a synonym for ____.

table