IF NOT EXISTS(SELECT * FROM SYS.COLUMNS WHERE NAME = 'DT_CAD' AND OBJECT_ID = OBJECT_ID('EST_PROD_REQ_TRANSF_LIB_EST_WMS_ENT'))
BEGIN
ALTER TABLE dbo.EST_PROD_REQ_TRANSF_LIB_EST_WMS_ENT ADD
	DT_CAD datetime NOT NULL CONSTRAINT DF_EST_PROD_REQ_TRANSF_LIB_EST_WMS_ENT_DT_CAD DEFAULT GETDATE()
END