MySQL - Find entries that refer to a specified index.

Posted by Conor H on Stack Overflow See other posts from Stack Overflow or by Conor H
Published on 2010-04-04T15:46:26Z Indexed on 2010/04/04 15:53 UTC
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mysql-query

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sql

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foreign-key-relationship

Hi,

So I have a booking system where I have a 'lesson_type' table with 'lesson_type_id' as PK. I have a constraint in place here so I can't delete a lesson_type if there are bookings made for that lesson_type.

I would like to be able to determine if this lesson_type_id is being referred to by any entries in the bookings table (or any other table for that matter) so I can notify the user gracefully. i.e. not have a mysql error be thrown when they try and delete a record.

What kind of query would I use for this?

Thanks.

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