December 2005
Intermediate to advanced
336 pages
4h 52m
English
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Chapter 25. Using Triggers
In this chapter, you’ll learn what triggers are, why they are used, and how. You’ll also look at the syntax for creating and using them.
Understanding Triggers
Note
Requires MySQL 5. Support for triggers was added to MySQL 5. As such, this chapter is applicable to MySQL 5 or later only.
MySQL statements are executed when needed, as are stored procedures. But what if you wanted a statement (or statements) to be executed automatically when events occur? For example:
Every time a customer is added to a database table, check that the phone number is formatted correctly and that the state abbreviation is in uppercase.
Every time a product is ordered, subtract the ordered quantity from the number in stock.
Whenever a row is deleted, ...
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O’Reilly covers everything we've got, with content to help us build a world-class technology community, upgrade the capabilities and competencies of our teams, and improve overall team performance as well as their engagement.Julian F.
I wanted to learn C and C++, but it didn't click for me until I picked up an O'Reilly book. When I went on the O’Reilly platform, I was astonished to find all the books there, plus live events and sandboxes so you could play around with the technology.Addison B.
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I'm always learning. So when I got on to O'Reilly, I was like a kid in a candy store. There are playlists. There are answers. There's on-demand training. It's worth its weight in gold, in terms of what it allows me to do.