![SQL SERVER - Unique Nonclustered Index Creation with IGNORE_DUP_KEY = ON - SQL Authority with Pinal Dave SQL SERVER - Unique Nonclustered Index Creation with IGNORE_DUP_KEY = ON - SQL Authority with Pinal Dave](https://blog.sqlauthority.com/i/b/ignoredup1.jpg)
SQL SERVER - Unique Nonclustered Index Creation with IGNORE_DUP_KEY = ON - SQL Authority with Pinal Dave
![SQL SERVER - Unique Nonclustered Index Creation with IGNORE_DUP_KEY = ON - SQL Authority with Pinal Dave SQL SERVER - Unique Nonclustered Index Creation with IGNORE_DUP_KEY = ON - SQL Authority with Pinal Dave](https://blog.sqlauthority.com/i/b/ignoredup2.jpg)
SQL SERVER - Unique Nonclustered Index Creation with IGNORE_DUP_KEY = ON - SQL Authority with Pinal Dave
![The primary key is the default clustered index in SQL Server and MySQL. This implies a 'clustered index penalty' on all non-clustered indexes. The primary key is the default clustered index in SQL Server and MySQL. This implies a 'clustered index penalty' on all non-clustered indexes.](https://use-the-index-luke.com/static/fig05_03_secondary_index_on_clustered_index.x1.A+AMD+Lr.png)
The primary key is the default clustered index in SQL Server and MySQL. This implies a 'clustered index penalty' on all non-clustered indexes.
![SQL SERVER - Unique Nonclustered Index Creation with IGNORE_DUP_KEY = ON - A Transactional Behavior - SQL Authority with Pinal Dave SQL SERVER - Unique Nonclustered Index Creation with IGNORE_DUP_KEY = ON - A Transactional Behavior - SQL Authority with Pinal Dave](https://blog.sqlauthority.com/i/b/duptr1.jpg)
SQL SERVER - Unique Nonclustered Index Creation with IGNORE_DUP_KEY = ON - A Transactional Behavior - SQL Authority with Pinal Dave
![SQL SERVER - Introduction to Filtered Index - Improve performance with Filtered Index - SQL Authority with Pinal Dave SQL SERVER - Introduction to Filtered Index - Improve performance with Filtered Index - SQL Authority with Pinal Dave](https://blog.sqlauthority.com/i/b/1_Index.gif)