Managing & Using MySQL, 2nd Edition

Complex Character Sets

Character sets requiring special string collating routines for sorting or multi-byte character support will need custom work a configuration file simply cannot handle. To accomplish this task, you will need to be familiar with C programming, as you will need to create several C source files. If you plan to attempt this, it is highly recommended that you study the existing ctype-*.c files and base yours on these.

As with simple character sets, you need to edit the sql/share/charsets/Index and configure.in files. Instead of a configuration file, however, you need to create a C source file called ctype -charset.c. In our case, this file will be ctype-elvish.c. You can get a head start with your character set file by copying the source file for a similar character set.

The first task in this source file is to define ctype , to_lower , to_upper , and sort_order . These are the same arrays you configured in the previous section, except they are defined as C arrays. You’ll need to create:

• ctype_ charset

• to_upper_ charset

• to_lower_ charset

• sort_order_ charset

For our example, we need to create ctype_elvish, to_upper_elvish, to_lower_elvish, and sort_order_elvish.

If you need string collating functions, you must write your own custom string collating functions. These functions should be named:

• my_strnncoll_ charset

• my_strnxfrm_ charset

• my_strcoll_ charset

• my_strxfrm_ charset

• my_like_range_ charset

We therefore need to create my_strnncoll_elvish, my_strnxfrm_elvish ...