2013/2/26 Thomas Kellerer <spam_ea...@gmx.net> > Don Parris wrote on 24.02.2013 23:20: > > With many thanks to Misa and others who helped out with my question >> about working with hierarchical data, I have now written a blog post >> on how I implemented the ltree module to solve my problem. >> >> http://dcparris.net/2013/02/**24/using-ltree-hierarchical-**postgresql/<http://dcparris.net/2013/02/24/using-ltree-hierarchical-postgresql/> >> >> Frankly, if you work with hierarchical data, I'm not sure I could >> recommend it strongly enough. I should think that even experienced, >> advanced SQL gurus would appreciate the simplicity ltree offers, when >> compared to the ugly table designs and recursive queries in order to >> work with hierarchical structures. >> >> I really hope this blog post will help others in the same boat. >> >> > How do you ensure referential integrity with this approach? > (i.e. make sure that all elements from the path column actually point to > an existing category) > > Thomas
Hi Thomas, Yes we met that problem and it further makes deeper problems... i.e. what if some category in up level - change his parent (updated path field) - path must be changed for all childs... Of several solutions - we have picked to use the best from both worlds... So we still use - parent_id column... and ltree is used just as materialized path - to improve performance... I think Materialized Views what comming in 9.3 - (I still havent seen how it works) - will help in that way - we will see...
