-- Fail to change the ISOK_Results.IRID
UPDATE isok_results
  SET irid = irid + 1
  WHERE irid = (SELECT MAX(ir.irid) FROM isok_results AS ir);
ERROR:  Error on UPDATE of @EXTSCHEMA@.ISOK_RESULTS
DETAIL:  Value (IRID) = (17): @EXTSCHEMA@.ISOK_RESULTS.IRID cannot be changed
CONTEXT:  PL/pgSQL function isok_results_func() line 12 at RAISE