When selecting an identifier, one should:
A) use intelligent keys.
B) use large composite keys instead of single-attribute surrogate keys.
C) choose a candidate key that will not change its value over the life of each instance of the entity type.
D) choose a candidate key such that for each instance of the entity, the attribute is guaranteed to have valid values or is null.
E) choose a candidate key that allows for duplicate values.

Question

Quizplus · Accepted Answer

Choosing a candidate key that will not change its value over the life of each instance of the entity type ensures that the identifier remains unique and does not lead to inconsistencies in the database. This is known as a stable identifier. Using intelligent keys or large composite keys may make the identifier more complex than necessary and can lead to errors or difficulty in maintenance. Choosing a candidate key that allows for duplicate values may also lead to inconsistencies in the database. Choosing a candidate key that guarantees valid values or null may be desirable but is not as crucial as choosing a stable identifier.

When Selecting an Identifier, One Should