SQL Trigger - Evolution - Block item saving without item group

SET ANSI_NULLS ON
GO
SET QUOTED_IDENTIFIER ON
GO
If EXISTS(Select [Name] from sysobjects where xType = 'TR' and [Name] = '_as_ItemGroups')
Drop Trigger _as_ItemGroups
Go
-- =============================================
-- Author:		Asamco BV, Alexander Toufexis
-- Create date: 23/03/2020
-- Description:	Trigger will block any items being created without a group (note; second trigger for INSERT part)
-- =============================================
CREATE TRIGGER [dbo].[_as_ItemGroups]
   ON  [dbo].[StkItem] 
   AFTER UPDATE
AS 
BEGIN
	-- SET NOCOUNT ON added to prevent extra result sets from
	-- interfering with SELECT statements.
	SET NOCOUNT ON;

	-- DECLARES:
	DECLARE @ItemID int
	DECLARE @GroupID int
	DECLARE @ItemCode varchar(100)
	DECLARE @ItemName varchar(100)
	DECLARE @Message varchar(500)
	DECLARE @DeletedCount as float

	IF (UPDATE(ItemGroup))
		BEGIN
    -- Insert statements for trigger here
	SELECT @ItemID = StockLink, @GroupID = ItemGroup,
	 @ItemCode = Code, @ItemName = inserted.Description_1
	 FROM Inserted


	DECLARE @isERROR bit
	SET @isERROR = 0

	IF (COALESCE(@GroupID,0) = 0)
		BEGIN
			SET @isERROR = 1
			SET @Message = 'No Group was selected for Item (' + @ItemCode + ' - ' + @ItemName + '). '
		END
	

	IF (@isERROR = 1)
		BEGIN
			RaisError(@Message, 16, 2);
			--select @isERROR = 1
		END
	END --IF (UPDATE(ItemGroup))
END

SET ANSI_NULLS ON
GO
SET QUOTED_IDENTIFIER ON
GO
If EXISTS(Select [Name] from sysobjects where xType = 'TR' and [Name] = '_as_ItemGroups_OnInsert')
Drop Trigger _as_ItemGroups_OnInsert
Go
-- =============================================
-- Author:		Asamco BV, Alexander Toufexis
-- Create date: 23/03/2020
-- Description:	Trigger will block any items being created without a group
-- Note: not "multi-create" supported properly. (all items would be blocked)
-- =============================================
CREATE TRIGGER [_as_ItemGroups_OnInsert]
    ON dbo.StkItem 
    INSTEAD OF INSERT
AS 
BEGIN
    SET NOCOUNT ON;
	/*Technical note: 
	using "instead of insert", because the creation of stock items is done using a direct insert, without proper roll-back code around it.
	As such, we need to do it this way.
	*/
	select * into #tmp from inserted;
	declare @Msg varchar(1000)
    IF EXISTS(SELECT * FROM inserted i where COALESCE(i.ItemGroup,'') = '')
		BEGIN
			SET @Msg = 'No group was selected for the item(s). Creation of item(s) cancelled.'
			RAISERROR(@Msg,16,1);
		END
	ELSE
		BEGIN
			--NOTE: row nr not properly updated, so in case of multiple inserts at the same time, this will cause an issue. to solve, make sure you get the "row_number" part working.
			ALTER TABLE #tmp DROP COLUMN StockLink; --TO DO: change to stock table ID. (StockLink)
			insert into dbo.StkItem select * from #tmp;
			drop table #tmp;
		END
END