|
Difference between Primary Key and Unique Key
Difference between Primary Key and Unique Key
- Both Primary Key and Unique Key gives uniqueness of the column on which they are defined.
- By default Unique Key creates a nonclustered index whereas Primary Key creates a clustered index on the column.
- A Primary key value cannot be NULL whereas Unique Key allows only one NULL.
|
User Comments:
Comment By
Amit
on
05/01/2011
Doubt here.
Unique Key allows only one NULL? or unique key allows null values(multiple null values). As every null is unique.
Post Your Comment :
|