ALTER TABLE FCT_MODELOCONTRATO ADD IDGERACONTFOR CHAR(1)
/

ALTER TABLE  FCT_MODELOCONTRATO ADD CONSTRAINT CK_IDGERACONTFOR CHECK (IDGERACONTFOR IN ('S', 'N'))
/

UPDATE FCT_MODELOCONTRATO
   SET IDGERACONTFOR = 'N'
 WHERE IDGERACONTFOR IS NULL
/