Altering the subtype of a string column

If you add a column with a string data type, you can specify its subtype in the ALTER TABLE statement. Subtypes are valid for string columns of data types CHAR, VARCHAR, and CLOB.

About this task

The subtype is stored in the FOREIGNKEY column of SYSIBM.SYSCOLUMNS.

An M in the FOREIGNKEY column when the MIXED DATA installation option is NO for a string column in an ASCII or EBCDIC table is interpreted as SBCS data, not MIXED data.

Procedure

To alter the subtype of an existing string column:

Issue the ALTER TABLE statement.

Begin general-use programming interface information. For example:

ALTER TABLE table-name ALTER COLUMN column-name 
      SET DATA TYPE altered-data-type

End general-use programming interface information.