- Both Keys are different. For Identifying each and every record in a table we use primary key.
- To apply additional uniqueness for other columns on the table we use Unique Key.
- Primary Keys are important for a table.
- Internal users use Primary Key whereas external users use unique key as it contains some meaningful information.
- When uniqueness is needed for multiple columns for a table, we use unique key for all columns and primary keys cannot be used in this case.
- Primary key uses clustered index by default and unique key uses Non-clustered index.
