FirebirdSQL logo
 SQL Language StructureCommon Language Elements 

Character Data Types

For working with character data, Firebird has the fixed-length CHAR and the variable-length VARCHAR data types.The maximum size of text data stored in these data types is 32,767 bytes for CHAR and 32,765 bytes for VARCHAR.The maximum number of characters that will fit within these limits depends on the character set used for the data under consideration.The collation does not affect this maximum, although it may affect the maximum size of any index that involves the column.

If no character set is explicitly specified when defining a character object, the default character set of the database — at time of defining the object — will be used.If the database does not have a default character set defined, the object gets the character set NONE.

Unicode

Most current development tools support Unicode, implemented in Firebird with the character sets UTF8 and UNICODE_FSS.UTF8 comes with collations for many languages.UNICODE_FSS is more limited and was previously used mainly by Firebird internally for storing metadata.Keep in mind that one UTF8 character occupies up to 4 bytes, thus limiting the size of CHAR fields to 8,191 characters (32,767/4).

Note

The actual “bytes per character” value depends on the range the character belongs to.Non-accented Latin letters occupy 1 byte, Cyrillic letters from the WIN1251 encoding occupy 2 bytes in UTF8, characters from other encodings may occupy up to 4 bytes.

The UTF8 character set implemented in Firebird supports the latest version of the Unicode standard, thus recommending its use for international databases.