Exam 5: Advanced Data Modeling

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

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 .

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

Explain the "no change over time" characteristic of a primary key.

Composite keys are useful as identifiers of weak entities,where the weak entity has a strong relationship with the parent entity.

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

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

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

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

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

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

completeness means that not every supertype occurrence is a member of a subtype.

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.

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

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

According to the "preferably single­attribute" characteristic of a primary key,the primary key:

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

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

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