Indexing Foreign Keys

Kim Tripp looks at the practice of adding non-clustered indexes on columns which make up foreign key constraints:

I’m going to tie today’s post with a question I received recently: if I have a table that has 6 foreign key columns/references should I create one index with all 6 foreign key columns in it, or should I create 6 individual indexes – one for each foreign key reference.

This is an interesting question with a few tangents to cover for our SQL101 series. I consider indexing foreign keys as part of my “Phase 1 of index tuning.” But, let’s go back to some basics before we dive into the answer on this one.

Read on for Kim’s thoughts on the topic and some good practices.

Related Posts

Implicit Parent Reference On Foreign Keys

Deborah Melkin shows us an interesting way of creating foreign keys: No matter how long you work with something, you can always find something that you never knew before. I found one about foreign keys this week. I was reviewing SQL scripts for coworkers and I noticed that the foreign keys were written without referencing […]

Read More

The Costs Of Rebuilding Indexes Online

Tibor Karaszi explains that TANSTAAFL (There A’int No Such Thing As A Free Lunch) applies to online index rebuilds: The time it takes to rebuild the index can be substantially longer for ONLINE. Many of us has other things to do with the database during night-time and/or weekends. Yes, these are the typical window in […]

Read More

Categories

March 2017
MTWTFSS
« Feb Apr »
 12345
6789101112
13141516171819
20212223242526
2728293031