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WHAT IS THE DIFFERENCE BETWEEN PRIMARY KEY(PK) CONSTRAINT
AND UNIQUE KEY(UK) + NOT NULL(NN) CONSTRAINT ASSIGN TO A
COLUMN ?
INSTEAD OF ASSIGNING PK ,WE CAN ASSIGN UK + NN TO A COLUMN.
WHAT ARE THE MARRITS AND DEMARITS BETWEEN THE ABOVE TWO?THE
ABOVE TWO ARE SAME,THEY DON'T ALLOW DUPLICATE AS WELL AS
NULL VALUES.
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Answer Posted / manikanta
By default primary key maintain clusterd index,All the
records are stored in stored order.By takeing this
advantage query will be execute fast.
Unique maintain nonclusted index,All the records are not in
stored order.
| Is This Answer Correct ? | 3 Yes | 0 No |
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