problem related to primary key

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hello guyzz

Is it possible to insert null value for primary key.
if yes then
plz help me to insert null value for primary key.

Posted 10-Dec-11 21:36pm

abhay7

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[no name] 11-Dec-11 3:38am

May I know why you need this?

2 solutions

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OriginalGriff · Accepted Answer · 2011-12-10T21:38:00

Solution 1

No.

"A table can have at most one primary key, but more than one unique key. A primary key is a combination of columns which uniquely specify a row. It is a special case of unique keys. One difference is that primary keys have an implicit NOT NULL constraint while unique keys do not."

Posted 10-Dec-11 21:38pm

OriginalGriff

Comments

Monjurul Habib 11-Dec-11 3:57am

5!

Rubaba 11-Dec-11 6:25am

5+

Pranit Kothari · Accepted Answer · 2011-12-10T21:39:00

Solution 2

Quote:
A table can have only one PRIMARY KEY constraint, and a column that participates in the PRIMARY KEY constraint cannot accept null values. Because PRIMARY KEY constraints guarantee unique data, they are frequently defined on an identity column.

PRIMARY KEY Constraints[^]

Posted 10-Dec-11 21:39pm

Pranit Kothari

Comments

Monjurul Habib 11-Dec-11 3:57am

5!

[no name] 11-Dec-11 4:12am

Thanks Monjurul.

Rubaba 11-Dec-11 6:26am

5+

[no name] 11-Dec-11 6:27am

Thanks Rubaba

mhamad zarif 11-Dec-11 6:53am

5

[no name] 11-Dec-11 6:56am

Thanks Mhamad!