Single-byte and multi-byte characters and locales

All built-in character data types can support single- and multibyte characters in the code set that the DB_LOCALE setting specifies. Locales for most European and Middle Eastern languages support only single-byte code sets, but the UTF-8 code set for the Unicode locale, and code sets for some East Asian locales, such as the Chinese GB18030-2000 locale, support multibyte logical characters.

When the SQL_LOGICAL_CHAR configuration parameter is enabled, you can instruct the database server to interpret explicit or default size parameters in declarations of built-in character data types as specifying the number of logical characters that can be stored, rather than the number of bytes. These logical character semantics are also applied to DISTINCT types whose base types are built-in character types, and to fields of built-in character types in declarations of named or unnamed ROW data types. This feature does not, however, support user-defined data types (UDTs) that store character strings. For more information about this feature, see the HCL Informix® Administrator's Reference description of the SQL_LOGICAL_CHAR configuration parameter.

The TEXT and CLOB data types also support single-byte or multibyte character data, but most built-in functions for manipulating character strings do not support TEXT nor CLOB data. For more information, see Large-Object Data Types.

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