Hi Javier
>Bhavbhuti, I made the family approach several years ago and had no problem, and I found that I did not have to write complicated code to maintain this approach. This is why I have kept it. The problem with hierarchies is old and has generated a lot of literature. If I remember well, I think Joe Celko (one of the best experts in SQL) has written about solving hierarchies.
Trees in SQL I have studied the article and since then I have had the guts to go for the hierarchial data for Accounts and Items master tables.