WHAT IS THE DIFFERENCE BETWEEN PRIMARY KEY(PK) CONSTRAINT AND UNIQUE KEY(UK) +

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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WHAT IS THE DIFFERENCE BETWEEN PRIMARY KEY(PK) CONSTRAINT AND UNIQUE KEY(UK) + NOT NULL(NN) CONSTRA..

Answer / adil khan

1.you can assign UK + NN TO A COLUMN behave like PRIMARY KEY(PK)
but (UK + NN) can not make any relation with any other table.
where as PRIMARY KEY(PK) can make relation with others tables.

Is This Answer Correct ?

6 Yes

0 No

WHAT IS THE DIFFERENCE BETWEEN PRIMARY KEY(PK) CONSTRAINT AND UNIQUE KEY(UK) + NOT NULL(NN) CONSTRA..

Answer / 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

WHAT IS THE DIFFERENCE BETWEEN PRIMARY KEY(PK) CONSTRAINT AND UNIQUE KEY(UK) + NOT NULL(NN) CONSTRA..

Answer / shwetalguglanicse

Primary key can be assigned to only 1 column in the table but
this is not with unique key
And UK allow duplicate value but PK does not .

Is This Answer Correct ?

2 Yes

8 No

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