10.14.3 Adding a Simple Collation to an 8-Bit Character Set

This section describes how to add a simple collation for an 8-bit character set by writing the <collation> elements associated with a <charset> character set description in the MySQL Index.xml file. The procedure described here does not require recompiling MySQL. The example adds a collation named latin1_test_ci to the latin1 character set.

1. Choose a collation ID, as shown in Section 10.14.2, “Choosing a Collation ID”. The following steps use an ID of 1024.

2. Modify the Index.xml and latin1.xml configuration files. These files are located in the directory named by the character_sets_dir system variable. You can check the variable value as follows, although the path name might be different on your system:

   mysql> SHOW VARIABLES LIKE 'character_sets_dir';
   +--------------------+-----------------------------------------+
   | Variable_name      | Value                                   |
   +--------------------+-----------------------------------------+
   | character_sets_dir | /user/local/mysql/share/mysql/charsets/ |
   +--------------------+-----------------------------------------+

3. Choose a name for the collation and list it in the Index.xml file. Find the <charset> element for the character set to which the collation is being added, and add a <collation> element that indicates the collation name and ID, to associate the name with the ID. For example:

   <charset name="latin1">
     ...
     <collation name="latin1_test_ci" id="1024"/>
     ...
   </charset>

4. In the latin1.xml configuration file, add a <collation> element that names the collation and that contains a <map> element that defines a character code-to-weight mapping table for character codes 0 to 255. Each value within the <map> element must be a number in hexadecimal format.

   <collation name="latin1_test_ci">
   <map>
    00 01 02 03 04 05 06 07 08 09 0A 0B 0C 0D 0E 0F
    10 11 12 13 14 15 16 17 18 19 1A 1B 1C 1D 1E 1F
    20 21 22 23 24 25 26 27 28 29 2A 2B 2C 2D 2E 2F
    30 31 32 33 34 35 36 37 38 39 3A 3B 3C 3D 3E 3F
    40 41 42 43 44 45 46 47 48 49 4A 4B 4C 4D 4E 4F
    50 51 52 53 54 55 56 57 58 59 5A 5B 5C 5D 5E 5F
    60 41 42 43 44 45 46 47 48 49 4A 4B 4C 4D 4E 4F
    50 51 52 53 54 55 56 57 58 59 5A 7B 7C 7D 7E 7F
    80 81 82 83 84 85 86 87 88 89 8A 8B 8C 8D 8E 8F
    90 91 92 93 94 95 96 97 98 99 9A 9B 9C 9D 9E 9F
    A0 A1 A2 A3 A4 A5 A6 A7 A8 A9 AA AB AC AD AE AF
    B0 B1 B2 B3 B4 B5 B6 B7 B8 B9 BA BB BC BD BE BF
    41 41 41 41 5B 5D 5B 43 45 45 45 45 49 49 49 49
    44 4E 4F 4F 4F 4F 5C D7 5C 55 55 55 59 59 DE DF
    41 41 41 41 5B 5D 5B 43 45 45 45 45 49 49 49 49
    44 4E 4F 4F 4F 4F 5C F7 5C 55 55 55 59 59 DE FF
   </map>
   </collation>

5. Restart the server and use this statement to verify that the collation is present:

   mysql> SHOW COLLATION WHERE Collation = 'latin1_test_ci';
   +----------------+---------+------+---------+----------+---------+
   | Collation      | Charset | Id   | Default | Compiled | Sortlen |
   +----------------+---------+------+---------+----------+---------+
   | latin1_test_ci | latin1  | 1024 |         |          |       1 |
   +----------------+---------+------+---------+----------+---------+