Database Chapter 5 Quiz

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

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

A primary key's main function is to uniquely identify a(n) _____ within a table.

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

A total completeness constraint is represented by _____.

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

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

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

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

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

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

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

Surrogate primary keys are especially helpful when there is no _____ key.

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.

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

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

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

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.

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

The preferred placement for a foreign key when working with a 1:1 relationship is to _____.

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

When selecting a foreign key placement for a 1:1 relationship, place the PK of the entity on the mandatory side in the entity on the optional side as a FK, and make the FK mandatory when _____.

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

_____ keys work with primary keys to properly implement relationships in the relational model.

_____ relationships occur when there are multiple relationship paths between related entities.