12.9.7 Adding a Collation for Full-Text Indexing

This section describes how to add a new collation for full-text searches. The sample collation is like latin1_swedish_ci but treats the '-' character as a letter rather than as a punctuation character so that it can be indexed as a word character. General information about adding collations is given in Section 10.4, “Adding a Collation to a Character Set”; it is assumed that you have read it and are familiar with the files involved.

To add a collation for full-text indexing, use this procedure:

  1. Add a collation to the Index.xml file. The collation ID must be unused, so choose a value different from 1000 if that ID is already taken on your system.

    <charset name="latin1">
    ...
    <collation name="latin1_fulltext_ci" id="1000"/>
    </charset>
    
  2. Declare the sort order for the collation in the latin1.xml file. In this case, the order can be copied from latin1_swedish_ci:

    <collation name="latin1_fulltext_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 5C 5B 5C 43 45 45 45 45 49 49 49 49
    44 4E 4F 4F 4F 4F 5D D7 D8 55 55 55 59 59 DE DF
    41 41 41 41 5C 5B 5C 43 45 45 45 45 49 49 49 49
    44 4E 4F 4F 4F 4F 5D F7 D8 55 55 55 59 59 DE FF
    </map>
    </collation>
    
  3. Modify the ctype array in latin1.xml. Change the value corresponding to 0x2D (which is the code for the '-' character) from 10 (punctuation) to 01 (small letter). In the following array, this is the element in the fourth row down, third value from the end.

    <ctype>
    <map>
    00
    20 20 20 20 20 20 20 20 20 28 28 28 28 28 20 20
    20 20 20 20 20 20 20 20 20 20 20 20 20 20 20 20
    48 10 10 10 10 10 10 10 10 10 10 10 10 01 10 10
    84 84 84 84 84 84 84 84 84 84 10 10 10 10 10 10
    10 81 81 81 81 81 81 01 01 01 01 01 01 01 01 01
    01 01 01 01 01 01 01 01 01 01 01 10 10 10 10 10
    10 82 82 82 82 82 82 02 02 02 02 02 02 02 02 02
    02 02 02 02 02 02 02 02 02 02 02 10 10 10 10 20
    10 00 10 02 10 10 10 10 10 10 01 10 01 00 01 00
    00 10 10 10 10 10 10 10 10 10 02 10 02 00 02 01
    48 10 10 10 10 10 10 10 10 10 10 10 10 10 10 10
    10 10 10 10 10 10 10 10 10 10 10 10 10 10 10 10
    01 01 01 01 01 01 01 01 01 01 01 01 01 01 01 01
    01 01 01 01 01 01 01 10 01 01 01 01 01 01 01 02
    02 02 02 02 02 02 02 02 02 02 02 02 02 02 02 02
    02 02 02 02 02 02 02 10 02 02 02 02 02 02 02 02
    </map>
    </ctype>
    
  4. Restart the server.

  5. To employ the new collation, include it in the definition of columns that are to use it:

    mysql> DROP TABLE IF EXISTS t1;
    Query OK, 0 rows affected (0.13 sec)
    
    mysql> CREATE TABLE t1 (
        a TEXT CHARACTER SET latin1 COLLATE latin1_fulltext_ci,
        FULLTEXT INDEX(a)
        ) ENGINE=InnoDB;
    Query OK, 0 rows affected (0.47 sec)
    
  6. Test the collation to verify that hyphen is considered as a word character:

    mysql> INSERT INTO t1 VALUEs ('----'),('....'),('abcd');
    Query OK, 3 rows affected (0.22 sec)
    Records: 3  Duplicates: 0  Warnings: 0
    
    mysql> SELECT * FROM t1 WHERE MATCH a AGAINST ('----' IN BOOLEAN MODE);
    +------+
    | a    |
    +------+
    | ---- |
    +------+
    1 row in set (0.00 sec)