CREATE PROCEDURE dbo.sp_renamediagram
	(
		@diagramname 		sysname,
		@owner_id		int	= null,
		@new_diagramname	sysname
	)
	WITH EXECUTE AS 'dbo'
	AS
	BEGIN
		set nocount on
		declare @theId 			int
		declare @IsDbo 			int
		declare @UIDFound 		int
		declare @DiagId			int
		declare @DiagIdTarg		int
		declare @u_name			sysname
		if((@diagramname is null) or (@new_diagramname is null))
		begin
			RAISERROR ('Invalid value', 16, 1);
			return -1
		end
		EXECUTE AS CALLER;
		select @theId = DATABASE_PRINCIPAL_ID();
		select @IsDbo = IS_MEMBER(N'db_owner'); 
		if(@owner_id is null)
			select @owner_id = @theId;
		REVERT;
		select @u_name = USER_NAME(@owner_id)
		select @DiagId = diagram_id, @UIDFound = principal_id from dbo.sysdiagrams where principal_id = @owner_id and name = @diagramname 
		if(@DiagId IS NULL or (@IsDbo = 0 and @UIDFound <> @theId))
		begin
			RAISERROR ('Diagram does not exist or you do not have permission.', 16, 1)
			return -3
		end
		-- if((@u_name is not null) and (@new_diagramname = @diagramname))	-- nothing will change
		--	return 0;
		if(@u_name is null)
			select @DiagIdTarg = diagram_id from dbo.sysdiagrams where principal_id = @theId and name = @new_diagramname
		else
			select @DiagIdTarg = diagram_id from dbo.sysdiagrams where principal_id = @owner_id and name = @new_diagramname
		if((@DiagIdTarg is not null) and  @DiagId <> @DiagIdTarg)
		begin
			RAISERROR ('The name is already used.', 16, 1);
			return -2
		end		
		if(@u_name is null)
			update dbo.sysdiagrams set [name] = @new_diagramname, principal_id = @theId where diagram_id = @DiagId
		else
			update dbo.sysdiagrams set [name] = @new_diagramname where diagram_id = @DiagId
		return 0
	END