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What is difference between UNIQUE constraint and PRIMARY KEY
constraint ?
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Answer / allin
The Primarykey Constraint= unique + Not Null constraints.
For the Unique the meaning it self it is telling unique
value. won't accept duplicate values.
Thanks & Regards,
RatnaRao
9833847339
| Is This Answer Correct ? | 9 Yes | 0 No |
Answer / naren
When ever you create a primary key constraint on perticular
column in a table it creates clustered index by default,
it cannot allow null values and a table having only one
primary key constraint. But in the case of Unique Key
constraint, it allow only one null value, it creates non-
clustered index by default and a table having multiple
unique key constraints.
Regards
Naren Krishna
| Is This Answer Correct ? | 8 Yes | 3 No |
Answer / kiran
if unique then it can have null
but if column has primary then it cannot have null values
and duplicate values
| Is This Answer Correct ? | 2 Yes | 1 No |
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