Which of the following is/are true about the PRIMARY KEY?
I. PRIMARY KEY must be UNIQUE within a relation
II. PRIMARY KEY may be NULL.
III. There can be multiple PRIMARY KEY within relation.1
Only I
2
Only I and II
3
Only II and III
4
I, II and II
Which of the following is/are true about the PRIMARY KEY?
I. PRIMARY KEY must be UNIQUE within a relation
II. PRIMARY KEY may be NULL.
III. There can be multiple PRIMARY KEY within relation.