GNU Info

(mysql.info)Adding character set

---

Next: Character arrays Prev: Languages Up: Localization

---

Enter node , (file) or (file)node

Adding a New Character Set
--------------------------

To add another character set to MySQL, use the following procedure.

Decide if the set is simple or complex.  If the character set does not
need to use special string collating routines for sorting and does not
need multi-byte character support, it is simple.  If it needs either of
those features, it is complex.

For example, `latin1' and `danish' are simple charactersets while
`big5' or `czech' are complex character sets.

In the following section, we have assumed that you name your character
set `MYSET'.

For a simple character set do the following:

  1. Add MYSET to the end of the `sql/share/charsets/Index' file Assign
     an unique number to it.

  2. Create the file `sql/share/charsets/MYSET.conf'.  (You can use
     `sql/share/charsets/latin1.conf' as a base for this).

     The syntax for the file very simple:

        * Comments start with a '#' character and proceed to the end of
          the line.

        * Words are separated by arbitrary amounts of whitespace.

        * When defining the character set, every word must be a number
          in hexadecimal format

        * The `ctype' array takes up the first 257 words. The
          `to_lower', `to_upper' and `sort_order' arrays take up 256
          words each after that.

     Note: Character arrays.

  3. Add the character set name to the `CHARSETS_AVAILABLE' and
     `COMPILED_CHARSETS' lists in `configure.in'.

  4. Reconfigure, recompile, and test.


For a complex character set do the following:

  1. Create the file `strings/ctype-MYSET.c' in the MySQL source
     distribution.

  2. Add MYSET to the end of the `sql/share/charsets/Index' file.
     Assign an unique number to it.

  3. Look at one of the existing `ctype-*.c' files to see what needs to
     be defined, for example `strings/ctype-big5.c'. Note that the
     arrays in your file must have names like `ctype_MYSET',
     `to_lower_MYSET', and so on.  This corresponds to the arrays in
     the simple character set. Note: Character arrays.  For a complex
     character set

  4. Near the top of the file, place a special comment like this:

          /*
           * This comment is parsed by configure to create ctype.c,
           * so don't change it unless you know what you are doing.
           *
           * .configure. number_MYSET=MYNUMBER
           * .configure. strxfrm_multiply_MYSET=N
           * .configure. mbmaxlen_MYSET=N
           */

     The `configure' program uses this comment to include the character
     set into the MySQL library automatically.

     The strxfrm_multiply and mbmaxlen lines will be explained in the
     following sections.  Only include them if you the string collating
     functions or the multi-byte character set functions, respectively.

  5. You should then create some of the following functions:

        * `my_strncoll_MYSET()'

        * `my_strcoll_MYSET()'

        * `my_strxfrm_MYSET()'

        * `my_like_range_MYSET()'

     Note: String collating.

  6. Add the character set name to the `CHARSETS_AVAILABLE' and
     `COMPILED_CHARSETS' lists in `configure.in'.

  7. Reconfigure, recompile, and test.

The file `sql/share/charsets/README' includes some more instructions.

If you want to have the character set included in the MySQL
distribution, mail a patch to <internals@lists.mysql.com>.