O'Reilly logo

MySQL Stored Procedure Programming by Steven Feuerstein, Guy Harrison

Stay ahead with the world's most comprehensive technology and business learning platform.

With Safari, you learn the way you learn best. Get unlimited access to videos, live online training, learning paths, books, tutorials, and more.

Start Free Trial

No credit card required

Conclusion

MySQL triggers allow you to execute stored program code whenever a DML statement is issued against a database table. In MySQL 5.0, triggers can be used to automate denormalization or logging.

Implementation of data validation in MySQL triggers is more of a challenge, as in MySQL there is no easy or straightforward way to raise an error condition or abort the transaction when validation fails. This will be remedied when the SIGNAL statement is implemented in MySQL 5.2. In this chapter we presented a workaround that does allow data validation triggers to be created in the interim, although the error text generated is far from ideal.

With Safari, you learn the way you learn best. Get unlimited access to videos, live online training, learning paths, books, interactive tutorials, and more.

Start Free Trial

No credit card required