Unicode CCSIDs

DB2® for z/OS® uses CCSIDs 367, 1200, and 1208 for Unicode data.

367: DB2 uses ASCII CCSID 367 for single-byte character data (SBCS) because the first 128 code points in Unicode UTF-8 are the same as the those in ASCII CCSID 367.
Therefore, DB2 uses CCSID 367 for CHAR, VARCHAR, and CLOB columns that are defined with FOR SBCS DATA in Unicode tables.
1208: DB2 uses CCSID 1208 for Unicode UTF-8 data, which DB2 always considers to be mixed data. This CCSID is the default CCSID value for Unicode tables.
Therefore, DB2 uses CCSID 1208 for CHAR, VARCHAR, and CLOB columns that are defined with FOR MIXED DATA in Unicode tables. FOR MIXED DATA is the default subtype specification.
1200: DB2 uses CCSID 1200 for Unicode UTF-16 data, which is double-byte data (DBCS). This CCSID applies to GRAPHIC and VARGRAPHIC Unicode data.
Therefore, DB2 uses CCSID 1200 for GRAPHIC, VARGRAPHIC, and DBCLOB columns in Unicode tables.

CCSIDs usually refer to a code page at a particular point in time. However, the Unicode CCSIDs that DB2 for z/OS uses are an exception. They can expand to include more characters as the Unicode standard grows. For example, CCSID 1200 can include the characters from the Unicode standard code pages 13488 (Unicode 2.0) and 17584 (Unicode 3.0). You can determine the CCSID for each Unicode standard code page by looking at the list of registered CCSIDs.

Because DB2 uses this architecture for CCSIDs, you can easily migrate to new versions of the Unicode standard by just updating your conversion image. However, the disadvantage to this architecture is that the CCSID value does not clearly tell you which characters are supported. To check which Unicode standard is currently supported for a particular conversion, issue the system DISPLAY UNI command.

Example DISPLAY UNI command: The following example output is from the command d uni,all:

  CUN3000I 09.33.37 UNI DISPLAY 754                                    
   ENVIRONMENT: CREATED       01/25/2010 AT 00.20.12                   
                MODIFIED      01/25/2010 AT 00.25.10                   
                IMAGE CREATED --/--/---- AT --.--.--                   
       SERVICE: CHARACTER      CASE           NORMALIZATION  COLLATION 
                STRINGPREP     BIDI           CONVERSION INF           
       STORAGE: ACTIVE       1995 PAGES                                
                FIXED           0 PAGES                                
                LIMIT      524288 PAGES                                
      CASECONV: ENABLED                                                
      CASE VER: UNI300  NORMAL  SPECIAL LOCALE                         
     NORMALIZE: DISABLED                                               
      NORM VER: NONE                                                   
       COLLATE: DISABLED                                               
    COLL RULES: NONE                                                   
   STRPROFILES: NONE                                                   
    CONVERSION: 00367-05123-R               00437-00819-R          
                00273-01208-R               01140-01252-E            
                01140-01252-R               00437-00850-E            
                00437-00850-R               01200(17584)-01140-E     
                01200(17584)-01141-E        01200(17584)-01142-E     
                01200(17584)-01144-E        00273-01252-E            
                00273-01252-R               01200(17584)-01148-E     
                00367-05210-R               00850-01200(13488)-R     
                01142-00367-E               00836-00367-E            
                01386-00836-R               01148-01200(17584)-R     
                01386-00935-RE              00437-01140-E            
                00437-01140-R               00437-01148-E            
                00437-01148-R               00437-01208-R            
    ...

The CONVERSION section of this output lists all of the CCSID conversions that are defined. For example, the line 01200(17584)-01141-E defines the conversion between CCSID 1200 and CCSID 1141. DB2 uses CCSID 1200 for Unicode UTF-16 data. The number in parentheses after CCSID 1200, 17584, means that in this conversion, CCSID 1200 uses Unicode standard 3.0. In the line 00850-01200(13488)-R, CCSID 1200 is followed by a different number, 13488. For this conversion, CCSID 1200 uses Unicode standard 2.0. The letters E and R represent the type of conversion. E means that the conversion is an enforced subset conversion. R means that the conversion is a round-trip conversion.