besoin d'aide pour un trigger

ALTER TRIGGER Trigger4
ON dbo.test_table1
AFTER INSERT, UPDATE, DELETE
AS 
BEGIN


DECLARE @FldsUpdated AS varCHAR(2000)

DECLARE @ColumnsUpdated VARBINARY(100)
SET @ColumnsUpdated = COLUMNS_UPDATED()

DECLARE @columnName AS varCHAR(255)
DECLARE @tableName AS varCHAR(255)
DECLARE @tableSchema AS varCHAR(255)
DECLARE @hasChanged AS INT
Declare @Totalstring as varchar(1000)

DECLARE curTableColumns CURSOR FOR
               SELECT TABLE_SCHEMA, TABLE_NAME, COLUMN_NAME
                                FROM INFORMATION_SCHEMA.COLUMNS
                               WHERE TABLE_NAME = 'test_table1'

set @totalstring = ''
set @FldsUpdated = ''
OPEN curTableColumns
FETCH NEXT FROM curTableColumns INTO @tableSchema, @tableName, @columnName


WHILE @@FETCH_STATUS = 0 
BEGIN
               SELECT @hasChanged = master.dbo.SYSTEM_IsBitSetInBitmask
                                (
                                @ColumnsUpdated,
                        (select colid 
                        from syscolumns 
                        where id = OBJECT_ID('dbo.test_table1')
                        and name = @columnName)
                               
                                )
               
            
         
            IF @hasChanged <> 0 
                  begin
                  
                     SET @FldsUpdated = @columnName
                  
                  set @totalstring = @totalstring + @FldsUpdated + ','
                      
            end
           FETCH NEXT FROM curTableColumns INTO @tableSchema, @tableName, @columnName
END
CLOSE curTableColumns
DEALLOCATE curTableColumns



insert into test_table2
(value1,value2,value3,columnsUpdated)
SELECT value1, value2, value3, @totalstring
FROM INSERTED
End





--Fonction master.dbo.SYSTEM_IsBitSetInBitmask



SET QUOTED_IDENTIFIER ON 
GO
SET ANSI_NULLS ON 
GO

ALTER  function SYSTEM_IsBitSetInBitmask  
(@bitmask varbinary(500), @colid int)  
    returns int  
as  

begin  
    declare @word smallint  
    declare @bit  smallint  
    declare @mask binary(2)  
    declare @mval int  
    declare @oldword binary(2)    
  
    if @colid < 1 return 0  
  
    SELECT @word = 1 + FLOOR((@colid -1)/16)  
  
    SELECT @bit = (@colid -1) % 16  
  
    SELECT @mval = POWER(2, @bit)  
    SELECT @mask = convert( binary(2), unicode( substring( convert( nchar(2), convert( binary(4), @mval ) ), 2, 1 ) ) )  
      
    SELECT @oldword = convert( binary(2), SUBSTRING( convert( nvarchar(64),@bitmask), @word, 1) )  
    IF @oldword IS NULL return 0  
  
    return  convert( smallint, @oldword ) & convert( smallint, @mask )  
end  

GO
SET QUOTED_IDENTIFIER OFF 
GO
SET ANSI_NULLS ON 
GO