Trigger to Update the OrderIndex of a specific id

SET ANSI_NULLS ON
GO
SET QUOTED_IDENTIFIER ON
GO
CREATE TRIGGER dbo.Update_OrderIndex 
   ON  dbo.cmspage 
   AFTER INSERT
AS 
BEGIN
	SET NOCOUNT ON;
	DECLARE @Num int
	SET @Num =	(SELECT	MAX(OrderIndex) + 1 
				 FROM	dbo.cmspage 
				 WHERE	applicationid IN (
					SELECT applicationid FROM inserted
				 ));
	UPDATE	dbo.cmspage
	SET		OrderIndex = @Num
	WHERE	id IN (
		SELECT id FROM inserted
	);
END
GO