This section describes how to add a UCA collation for a Unicode character set by writing the <collation> element within a <charset> character set description in the MySQL Index.xml file. The procedure described here does not require recompiling MySQL. It uses a subset of the Locale Data Markup Language (LDML) specification, which is available at http://www.unicode.org/reports/tr35/. In 5.0, this method of adding collations is supported as of MySQL 5.0.46. With this method, you need not define the entire collation. Instead, you begin with an existing “base” collation and describe the new collation in terms of how it differs from the base collation. The following table lists the base collations of the Unicode character sets for which UCA collations can be defined.

The following sections show how to add a collation that is defined using LDML syntax, and provide a summary of LDML rules supported in MySQL.