IF NOT EXISTS (SELECT * FROM SYS.COLUMNS WHERE NAME = 'CARAC_TRIB' AND OBJECT_ID = OBJECT_ID('EST_TRIB_OPER_MVA'))
BEGIN
	ALTER TABLE EST_TRIB_OPER_MVA ADD CARAC_TRIB INT NOT NULL CONSTRAINT DF_EST_TRIB_OPER_MVA_CARAC_TRIB DEFAULT 3
END
