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

Question

Quizplus · Accepted Answer

Choosing a candidate key that will not change its value over the life of each instance of the entity type is the best choice for selecting an identifier because it ensures that the uniqueness of the identifier is preserved even if the other attributes of the entity change. This is important for maintaining relationships between entities and ensuring data integrity. Using intelligent keys (A) or large composite keys (B) can lead to performance issues and make it difficult to maintain referential integrity. Choice D is also important, but it is not the best choice on its own since it does not guarantee the uniqueness of the identifier.

When Selecting an Identifier,one Should