FiltersDone

Question type

Essay

Multiple Choice

Short Answer

True False

Matching

Exam 5: Advanced Data Modeling

Show Answer

Share

---

All types

Filters

Study FlashcardsPractice ExamLearn

Question 31

Multiple Choice

Review LaterAdd Note

Review Later

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

A) not equality
B) less than
C) greater than
D) equality

E) All of the above
F) B) and D)

Correct Answer

verified

Show Answer

Question 32

Short Answer

Review LaterAdd Note

Review Later

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

Correct Answer

verified

Show Answer

Question 33

True/False

Review LaterAdd Note

Implementing non-overlapping subtypes requires the use of one discriminator attribute for each subtype.

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

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

Specialization is based on grouping ____________________ characteristics and relationships of the subtypes.

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

At the implementation level,the supertype and its subtype(s)depicted in the specialization hierarchy maintain a 1:1 relationship.

Overlapping subtypes are subtypes that contain a unique subset of the supertype entity set.

The "____" characteristic of a primary key states that: The PK should not have embedded semantic meaning.An attribute with embedded semantic meaning is probably better used as a descriptive characteristic of the entity rather than as an identifier.

The most common design trap is known as a(n)____________________.

A ____ occurs when you have one entity in two 1:M relationships to other entities,thus producing an association among the other entities that is not expressed in the model.

Partial completeness is symbolized by ____.

In what two cases are composite primary keys particularly useful?

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

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

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

____ data refer to data whose values change over time and for which you must keep a history of the data changes.

Subtypes that contain nonunique subsets of the supertype entity set are known as ____________________ .

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