Character encoding schemes

Each character string is further defined as one of:

Bit data
Data that is not associated with a coded character set and is therefore never converted. The CCSID for bit data is 65535.
SBCS data
Data in which every character is represented by a single byte. Each SBCS data character string has an associated CCSID. If necessary, an SBCS string is converted before it is used in an operation with a character string that has a different CCSID.
Mixed data
Data that may contain a mixture of characters from a single-byte character set (SBCS) and a double-byte character set (DBCS). Each mixed string has an associated CCSID. If necessary, a mixed data character string is converted before an operation with a character string that has a different CCSID. If mixed data contains a DBCS character, it cannot be converted to SBCS data.
Unicode data
Data that contains characters represented by one or more bytes. Each Unicode character string is encoded using UTF-8. The CCSID for UTF-8 is 1208.

The database manager does not recognize subclasses of double-byte characters, and it does not assign any specific meaning to particular double-byte codes. However, if you choose to use mixed data, then two single-byte EBCDIC codes are given special meanings:

In order for the database manager to recognize double-byte characters in a mixed data character string, the following condition must be met:

The length of a mixed data character string is its total number of bytes, counting two bytes for each double-byte character and one byte for each shift-out or shift-in character.

When the job CCSID indicates that DBCS is allowed, CREATE TABLE will create character columns as DBCS-Open fields, unless FOR BIT DATA, FOR SBCS DATA, or an SBCS CCSID is specified. The SQL user will see these as character fields, but the system database support will see them as DBCS-Open fields. For a definition of a DBCS-Open field, see the Database programming topic.