Database Quiz 2

________ 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

A member of a subtype does NOT necessarily have to be a member of the supertype.

False

There can be multivalued attributes in a relation

False

When transforming a one-to-one relationship, a new relation is always created

False

A well-structured relation contains minimal redundancy and allows users to manipulate the relation without errors or inconsistencies.

True

Entity clustering is a methodology for grouping one or more entity types and associated relationships into a single abstract entity type.

True

The default primary key for an associative relation consists of the two primary key attributes from the other two relations.

True

one property of a relation is that each attribute within a relation has a unique name

True

The property by which subtype entities possess the values of all attributes of a supertype is called:

attribute inheritance

a primary key that consists of more than one attribute is called a:

composite key

In the SQL language, the ________ statement is used to make table definitions.

create table

An attribute in a relation of a database that serves as the primary key of another relation in the same database is called a:

foreign key

the entity integrity rule states that:

no primary key attribute can be null

A two-dimensional table of data sometimes is called a

relation

The process of defining one or more subtypes of a supertype and forming relationships is called:

specialization