IF NOT EXISTS(SELECT C.NAME FROM SYS.COLUMNS C WHERE C.NAME = 'FLAG_DESC_USO_CONTINUO' AND C.OBJECT_ID = OBJECT_ID('EST_PROD_TBL_DESC'))
	BEGIN 
		ALTER TABLE EST_PROD_TBL_DESC ADD FLAG_DESC_USO_CONTINUO INT 
		ALTER TABLE EST_PROD_TBL_DESC ADD CONSTRAINT DF_FLAG_DESC_USO_CONTINUO DEFAULT 0 FOR FLAG_DESC_USO_CONTINUO
	END
	
GO

IF EXISTS(SELECT C.NAME FROM SYS.COLUMNS C WHERE C.NAME = 'FLAG_DESC_USO_CONTINUO' AND C.OBJECT_ID = OBJECT_ID('EST_PROD_TBL_DESC'))	
	BEGIN 
		UPDATE EST_PROD_TBL_DESC SET FLAG_DESC_USO_CONTINUO = 0 WHERE FLAG_DESC_USO_CONTINUO IS NULL
	END 