The Hexadecimal transform passes the hexadecimal value of the COBOL data. The column should be defined as char and be twice the size of the COBOL record field; that is, a field containing a PIC S9(5) COMP-3 data item, which is a three-byte field, will return six bytes of hexadecimal information.
The Hexadecimal transform is useful for tracking down problem data. For example, if you have a column that returns the SQL error "Invalid Numerics", you can use the Hexadecimal transform and see what data is in the field.