Chapter 5

At the implementation level, the supertype and its subtype(s) depicted in a specialization hierarchy maintain a(n) _____ relationship.

1:1

_____ is the bottom-up process of identifying a higher-level, more generic entity supertype from lower-level entity subtypes.

Generalization

Composite primary keys are particularly useful as identifiers of composite entities, where each primary key combination is allowed only once in the _____ relationship.

M:N

Which of the following is a specialization hierarchy disjoint constraint scenario in case of partial completeness?

Subtype discriminator can be null.

Which of the following is a specialization hierarchy overlapping constraint scenario in case of partial completeness?

Supertype has optional subtypes.

An entity cluster is formed by combining multiple interrelated entities into _____.

a single abstract entity object

A partial completeness constraint is represented by _____.

a single horizontal line under a circle

The purpose of an entity _____ is to simplify an entity-relationship diagram (ERD) and thus enhance its readability.

cluster

In the context of total completeness, in a(n) _____, every supertype occurrence is a member of only one subtype.

disjoint constraint

A total completeness constraint is represented by a _____.

double horizontal line under a circle

The extended entity relationship model (EERM) is sometimes referred to as the _____.

enhanced entity relationship model

A(n)_____ is a generic entity type that is related to one or more entity subtypes.

entity supertype

The default comparison condition for the subtype discriminator attribute is the _____ comparison.

equality

The property of _____ enables an entity subtype to inherit the attributes and relationships of the supertype.

inheritance

A specialization hierarchy can have _____ level(s) of supertype/subtype relationships.

many

A _____ key is a real-world, generally accepted identifier used to uniquely identify real-world objects.

natural

If one exists, a data modeler uses a _____ as the primary key of the entity being modeled.

natural identifier

The "_____" characteristic of a primary key states that the primary key should not have embedded semantic meaning.

nonintelligent

Overlapping subtypes are subtypes that contain _____ subsets of the supertype entity set.

nonunique

Within a specialization hierarchy, every subtype can have _____ supertype(s) to which it is directly related.

only one

In the context of total completeness, in a(n) _____, every supertype occurrence is a member of at least one subtype.

overlapping constraint

One important inheritance characteristic is that all entity subtypes inherit their _____ key attribute from their supertype.

primary

The most important characteristic of an entity is its _____ key, used to uniquely identify each entity instance.

primary

The "_____" characteristic of a primary key states that the selected primary key must not be composed of any attribute(s) that might be considered a violation.

security-compliant

According to the "preferably single-attribute" characteristic of a primary key, the primary key:

should have the minimum number of attributes possible.

The _____ depicts the arrangement of higher-level entity supertypes (parent entities) and lower-level entity subtypes (child entities).

specialization hierarchy

A(n) _____ is the attribute in the supertype entity that determines to which entity subtype each supertype occurrence is related.

subtype discriminator

A _____ is a primary key created by a database designer to simplify the identification of entity instances.

surrogate key

Nonoverlapping subtypes are subtypes that contain a(n) _____ subset of the supertype entity set.

unique

The "_____" characteristic of a primary key states that the primary key must uniquely identify each entity instance, must be able to guarantee unique values, and must not contain nulls.

unique values