Primary key
|
Unique Key
|
1- Primary
key doesn’t have a null value.
2- A table can have only one primary key.
3- By
default primary key has a clustered index.
|
The unique key can hold null value but only once.
A table can have more than one unique key. By default, the Unique key has a non- clustered index. |
Difference between Primary key and Unique Key
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