How Foreign Key Constraints Affect Indexes

(Doc ID 2237820.1)

Last updated on FEBRUARY 25, 2017

Applies to:

MySQL Server - Version 5.5 and later
Information in this document applies to any platform.

Goal

Qn1: How can I find what tables are using foreign keys in my schema?
 
Qn2: Are indexes on foreign key columns created automatically or do I have to create them?
 
Qn3: Show if no index is created for the foreign key column, one will be automatically created?
 
Qn4: What happens if I create a foreign key and an index already exists on that column?
 

Solution

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