From: Martijn Tonies
Date: March 20 2006 7:24am
Subject: Re: Discussion: the efficiency in using foreign keys
List-Archive: http://lists.mysql.com/mysql/195968
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Hi,

> This is a fundamental concept in RDBMS: the use of foreign keys in 
> database design.
> 
> I'd just like to poll the community here, on whether it is a best 
> practice, or practically essential to 'link' related tables by use of 
> foreign keys.
> 
> For myself, I usually do all the validity checking when adding a new 
> record that references a record id from another table. I understand that 
> this may not be efficient because it becomes 2 database calls (and db 
> calls are expensive in high-load environments).
> 
> What are the advantages/ disadvantages in using foreign keys? In MySQL, 
> this means one cannot use MyISAM. Do you place a lot of triggers as well?

When it comes to referential constraints, the answer is simple:
ALWAYS put them on the database.

Anyway who answers differently either never had to recover
a database that was trashed by the lack of integrity constraints
or has no ide what he's talking about.

Most probably, this statement will get me tons of e-mail again ;-)

Martijn Tonies
Database Workbench - development tool for MySQL, and more!
Upscene Productions
http://www.upscene.com
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http://blog.upscene.com/martijn/
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