Exam 5: Advanced Data Modeling

The completeness constraint can be partial or total.

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

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

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

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

A design trap occurs when a relationship is improperly or incompletely identified and is therefore represented in a way that is not consistent with the real world.

The entity supertype contains the common characteristics and the entity subtypes contain the unique characteristics of each entity subtype.

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

Describe specialization and generalization.

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

____________________ completeness means that every supertype occurrence must be a member of at least one subtype.

Generalization is based on grouping unique characteristics and relationships of the subtypes.

The main concern with redundant relationships is that they remain ____________________ across the model.

What is an entity cluster?

An entity supertype can have disjoint or overlapping entity subtypes.

Entity supertypes and subtypes are organized in a specialization hierarchy.

What do specialization hierarchies do?

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

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

Some designs use redundant relationships as a way to simplify the design.