PHPMaster.com: Action Automation with MySQL Triggers
For the MySQL users out there, PHPMaster.com has a new tutorial showing you how to use triggers in your database to perform automatic actions on things like "before update" or "after insert".
By making MySQL do more work through triggers, the PHP side of my project was greatly simplified. So, it is the intention of this article to give you some insight into the creation and usage of MySQL triggers, so that by the end of this reading you can make use of them in your own projects.
They start by explaining what triggers are and how they're created on the database side (with an example syntax). They apply one to a more practical situation - helping keep data integrity on a revenue table based on the data inserted into an events tracking table. Their trigger ("CostCalc") calculates the time of the event on update and updates the revenue table with the correct cost. Also included is the sample PHP code (an "EventHandler") that updates the event records. The trigger fires transparently in the background with no need for the PHP script to make any additional calls.