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All Forums  SQL Server 2000 Forums  SQL Server Development (2000)  How to check for circular referencing

Author  Topic  Sanette Starting Member 3 Posts Posted - 2002-07-19 : 03:08:59 It would be great if someone can help me out on this one. I have the following data: ITEMFROM ITEMTO ALLOWED? ItemA ItemB Yes ItemA ItemC Yes ItemB ItemD Yes ItemC ItemD Yes ItemD ItemB No ItemD ItemA No ItemE ItemB Yes ItemF ItemB Yes ItemF ItemC Yes ItemA ItemA No My current code looks like this: IF (SELECT COUNT(*) FROM tbl_SupercessionHeader WHERE ItemMasterIDFrom = @iFromItemMasterID ) > 0 BEGIN RETURN END IF (SELECT COUNT(*) FROM tbl_SupercessionHeader WHERE ItemMasterIDFrom = @iToItemMasterID ) > 0 BEGIN RAISERROR ('Item has circular referencing',16,1) RETURN END The problem with the code is that if an Item is already superceded it cannot be superceded again, e.g. ItemA --> ItemB, ItemA --> ItemC will not be allowed (and it should). Any ideas?????