IF not EXISTS (SELECT * FROM sys.foreign_keys WHERE object_id = OBJECT_ID(N'[dbo].[FK_EST_NF_ENT_DAR_IT_GLB_NT_OP]') AND parent_object_id = OBJECT_ID(N'[dbo].[EST_NF_ENT_DAR_IT]'))
begin
ALTER TABLE dbo.EST_NF_ENT_DAR_IT ADD CONSTRAINT
	FK_EST_NF_ENT_DAR_IT_GLB_NT_OP FOREIGN KEY
	(
	CD_NT_OP
	) REFERENCES dbo.GLB_NT_OP
	(
	CD_NT_OP
	) ON UPDATE  NO ACTION 
	 ON DELETE  NO ACTION 
end	