Check if field is auto incrementing?

[Catfish]

How can I find out if a field (or primary key) is set to be auto incrementing? I checked information_schema COLUMNS table but there doesn't seem to be a field for this.

 

I want to be able to identify this to exclude the field from an INSERT query in a PHP script. My script is going to be usable for any table, so I need it to check for this and remove the SQL entries for the field that is auto incrementing.

 

SOLVED: The table I was working with didn't have the primary key as auto_incrementing. This info is held in the EXTRA field of the COLUMNS table in the information_schema database.