Difference between primary key and unique key ?
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Answer Posted / hemendra singh chaudhary
In the Table a primary key constraint column cannot holding
the null values.whereas unique constraint colum can holding
the null values.
Ex.|--------------------|
| ID(P) | Name(U) | #ID(P) ->It's a Primary Key
|--------------------| * Its a Not Null
| 1 | Hemendra | * A table Contain 1 Primary
| 2 | Neeraj | Key.
| 3 | PremJe | #Name(U)->It's a Unique Key
|NotNull |canbe Null| * Its can contain Null Value
|--------------------| * A table Contain more
than 1 unique Key.
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