Difference between Primary Key and Unique Key

By default, primary key creates clustered index on the column and then enforces the uniqueness of the column whereas the unique key, by default creates a non-clustered index.

Primary Key

  • By default, creates Clustered index
  • Doesn’t allow null
  • Table can have only one Primary Key ( Can include multiple columns together )

Unique Key

  • By default, creates non clustered index
  • Accepts null value
  • Table can have many unique keys

Leave A Reply

Your email address will not be published. Required fields are marked *

You May Also Like

In this blog post, let’s learn about the error message “1459 – An error occurred while accessing the database mirroring...
In this blog post, let’s learn about the error message “7937 – Columnstore index has one or more missing column...