InterviewSolution
Saved Bookmarks
| 1. |
If a1, a2, a3 are attributes in a relation and S is another relation, which of the following is an incorrect specification of an integrity constraint?(a) primary key(a1, a2, a3)(b) primary key(a1)(c) foreign key(a1, a2) references S(d) foreign key(a1, a2) |
|
Answer» Right answer is (d) foreign key(a1, a2) Explanation: Whenever the integrity constraint foreign key is mentioned, the attributes that are the foreign keys should always be referenced from the relation in which they are primary keys. |
|