IF NOT EXISTS(SELECT * FROM	INFORMATION_SCHEMA.COLUMNS	WHERE TABLE_NAME='EST_ALCADA_CP_PED_ALCADAS_LIB' AND COLUMN_NAME='OBS_LIB')
BEGIN
ALTER TABLE dbo.EST_ALCADA_CP_PED_ALCADAS_LIB ADD
	OBS_LIB varchar(MAX) NOT NULL CONSTRAINT DF_EST_ALCADA_CP_PED_ALCADAS_LIB_OBS_LIB DEFAULT ''
END