MySQL Reference Manual for version 4.0.18.
21.2 Adding New Functions to MySQL
There are two ways to add new functions to MySQL:
- You can add the function through the user-defined function (UDF)
interface. User-defined functions are added and removed dynamically using
the
CREATE FUNCTION
and DROP FUNCTION
statements.
See section CREATE FUNCTION
.
- You can add the function as a native (built in) MySQL function.
Native functions are compiled into the
mysqld
server and become
available on a permanent basis.
Each method has advantages and disadvantages:
-
If you write a user-defined function, you must install the object file
in addition to the server itself. If you compile your function into the
server, you don't need to do that.
-
You can add UDFs to a binary MySQL distribution. Native functions
require you to modify a source distribution.
-
If you upgrade your MySQL distribution, you can continue to use your
previously installed UDFs. For native functions, you must repeat your
modifications each time you upgrade.
Whichever method you use to add new functions, they may be used just like
native functions such as ABS()
or SOUNDEX()
.
This document was generated
by rdg (Feb 25 2004)
using texi2html