The following item-descriptor fields provide information about a column that has a distinct type as its data type:
Set this field if the source type of the distinct type is an opaque data type. This integer value must correspond to a value in the source column for the row of the sysxtdtypes system catalog table whose extended_id value matches that of the distinct type you are setting.
This value is the data type constant for the built-in data type that is the source type for the distinct type. The codes for the SOURCETYPE field are the same as those for the TYPE field (page Setting the TYPE or ITYPE Field). This integer value must correspond to the value in the type column for the row of the sysxtdtypes system catalog table whose extended_id value matches that of the distinct type you are setting.
For more information on the sysxtdtypes system catalog table, see the IBM Informix Guide to SQL: Reference.
You can use a DESCRIBE statement to modify the contents of a system-descriptor area after it is set.
After you use DESCRIBE on a SELECT or an INSERT statement, you must check to determine whether the TYPE field is set to either 11 or 12 to indicate a TEXT or BYTE data type. If TYPE contains an 11 or a 12, you must use the SET DESCRIPTOR statement to reset TYPE to 116, which indicates FILE type.
Related statements: ALLOCATE DESCRIPTOR, DEALLOCATE DESCRIPTOR, DECLARE , DESCRIBE, EXECUTE , FETCH , GET DESCRIPTOR , OPEN , PREPARE, and PUT
For more information on system-descriptor areas, refer to the IBM Informix ESQL/C Programmer's Manual.