Users have the option to change the default constraint values available for a session using the SET SESSION CONSTRAINT statement.
Based on Example: Loading Tables without User OVERRIDE Privileges, U1 might reset the session default Countries constraint:
SET SESSION CONSTRAINT = Countries (UK, Canada);
The session constraint value is changed from the ‘E0’xb to '60'xb (hex representation of 01100000). Subsequent inserts during the session default to '60'xb for the Countries constraint column.
You can display the hex string for the default constraint values using the HELP SESSION CONSTRAINT statement.