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