Chapter 14. Extending MySQL

Within the spectrum of relational database management systems, MySQL has always occupied a unique position. Its open source nature and fast performance have made it the most popular database server for small-to-medium web-based applications. However, its lack of support for features such as transactions, foreign keys, row-level locking, and stored procedures have made many pass over it for other applications, though its performance would otherwise be beneficial.

As MySQL has matured over time, various solutions have emerged for all these problems. Through alternative table types such as Berkeley DB and InnoDB, MySQL now supports transactions and row-level locking. Thanks to the InnoDB table type, the MySQL team has added support for foreign keys.

One of MySQL's virtues is that it is intended to be extended. For example, stored procedures remain the most requested Oracle/SQL Server/Sybase feature lacking in MySQL. Though MySQL currently has no support for stored procedures (it probably will by the time you read this book), you can extend MySQL by writing your own user-defined functions (UDFs). In this chapter, we examine how to write your own functions and add character sets to MySQL.