When Selecting an Identifier,one Should

question 47

Multiple Choice

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