Comments on: MySQL Triggers: How do you abort an INSERT, UPDATE or DELETE with a trigger? http://www.brokenbuild.com/blog/2006/08/15/mysql-triggers-how-do-you-abort-an-insert-update-or-delete-with-a-trigger/ Databases, code and all things agile. Thu, 09 Feb 2012 09:45:10 +0000 http://wordpress.org/?v=2.6.3 By: Design of mysql DB to avoid having a table with mutually exclusive fields | DEEP in PHP http://www.brokenbuild.com/blog/2006/08/15/mysql-triggers-how-do-you-abort-an-insert-update-or-delete-with-a-trigger/#comment-93776 Design of mysql DB to avoid having a table with mutually exclusive fields | DEEP in PHP Sat, 12 Mar 2011 15:04:23 +0000 http://www.brokenbuild.com/blog/2006/08/15/mysql-triggers-how-do-you-abort-an-insert-update-or-delete-with-a-trigger/#comment-93776 <p>[...] are all the same, so i’m thinking about using only one table. I’ve read here and here (even if i don’t understand fully this example) that i can enforce a mysql rule to have [...]</p> [...] are all the same, so i’m thinking about using only one table. I’ve read here and here (even if i don’t understand fully this example) that i can enforce a mysql rule to have [...]

]]> By: Glen Edmonds http://www.brokenbuild.com/blog/2006/08/15/mysql-triggers-how-do-you-abort-an-insert-update-or-delete-with-a-trigger/#comment-93651 Glen Edmonds Thu, 02 Dec 2010 01:27:07 +0000 http://www.brokenbuild.com/blog/2006/08/15/mysql-triggers-how-do-you-abort-an-insert-update-or-delete-with-a-trigger/#comment-93651 <p>Here's a much simpler implementation of the hack that doesn't require all that PSQL cruft:</p> <p>drop table your_meaningful_message_goes_here;</p> <p>This will throw an exception that looks like this:</p> <p>ERROR 1051 (42S02): Unknown table 'your_meaningful_message_goes_here'</p> <p>At least the user will get the message.</p> Here’s a much simpler implementation of the hack that doesn’t require all that PSQL cruft:

drop table your_meaningful_message_goes_here;

This will throw an exception that looks like this:

ERROR 1051 (42S02): Unknown table ‘your_meaningful_message_goes_here’

At least the user will get the message.

]]> By: Liam http://www.brokenbuild.com/blog/2006/08/15/mysql-triggers-how-do-you-abort-an-insert-update-or-delete-with-a-trigger/#comment-62841 Liam Tue, 22 Apr 2008 06:52:45 +0000 http://www.brokenbuild.com/blog/2006/08/15/mysql-triggers-how-do-you-abort-an-insert-update-or-delete-with-a-trigger/#comment-62841 <p>Thanks for the assist; coming from PostgreSQL, MySQL triggers and functions seem like a hell of a mess...</p> <p>I would say it's the best place to enforce business rules if you want consistent data. There might be many ways in your application to edit the data in a given table, and you can check things in those many places; or you can enforce it at a database level and then handle that appropriately further up the stack.</p> <p>The second way is much more simple and will catch problems even if checks are not followed properly in a piece of application code.</p> Thanks for the assist; coming from PostgreSQL, MySQL triggers and functions seem like a hell of a mess…

I would say it’s the best place to enforce business rules if you want consistent data. There might be many ways in your application to edit the data in a given table, and you can check things in those many places; or you can enforce it at a database level and then handle that appropriately further up the stack.

The second way is much more simple and will catch problems even if checks are not followed properly in a piece of application code.

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