Exam 5: Advanced Data Modeling

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

The "____" characteristic of a primary key states the following: The PK must uniquely identify each entity instance.A primary key must be able to guarantee unique values.It cannot contain nulls.

The "____" characteristic of a primary key states the following: The selected primary key must not be composed of any attribute(s)that might be considered a security risk or violation.For example,using a Social Security number as a PK in an EMPLOYEE table is not a good idea.

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

Partial completeness is symbolized by ____.

An entity cluster is considered "virtual" or "____________________" in the sense that it is not actually an entity in the final ERD.

The relationships depicted within the specialization hierarchy are sometimes described in terms of "is-a" relationships.

____ is a generic entity type that is related to one or more entity subtypes.

Composite primary keys are particularly useful as identifiers of composite entities,where each primary key combination is allowed ____________________ in the M:N relationship.

Usually,a data modeler uses a natural identifier as the ____________________ of the entity being modeled,assuming that the entity has a natural identifier.

Within a specialization hierarchy,a supertype can exist only within the context of a subtype.

If you use a surrogate key,you must ensure that the candidate key of the entity in question performs properly through the use of the "____________________" and "not null" constraints.

From a data modeling point of view,____________________ refer to data whose values change over time and for which you must keep a history of the data changes.

An entity cluster is a "virtual" entity type used to represent multiple entities and relationships in the ERD.

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

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

The ____________________ constraint specifies whether each entity supertype occurrence must also be a member of at least one subtype.

Disjoint subtypes are also known as ____________________ subtypes.

Specialization is the top-down process of identifying lower-level,more specific entity subtypes from a higher-level entity supertype.

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