Re: How to store directory like structures?
От | PFC |
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Тема | Re: How to store directory like structures? |
Дата | |
Msg-id | op.son4qhnvth1vuj@localhost обсуждение исходный текст |
Ответ на | How to store directory like structures? (Axel Straschil <axel@straschil.com>) |
Список | pgsql-sql |
Use the ltree datatype !It's made specifically for this purpose.http://www.sai.msu.su/~megera/postgres/gist/ On Sun, 03 Apr 2005 12:13:48 +0200, Axel Straschil <axel@straschil.com> wrote: > Hello! > > I want to store some structure like: > > CREATE TABLE node > ( > nodeid SERIAL PRIMARY KEY, > parent INT REFERENCES node(nodeid) > ON UPDATE CASCADE ON DELETE CASCADE, > label TEXT, > UNIQUE (parent, label), > ... > data > ... > ); > > The label is used to map a node to a directory like strukture, so i can > have a function directory_for(nodeid) which gives me > /root_label/parent_label/parent_label/my_label (root labels have NULL as > parent) > > The problem is the ammount of queries when i've got deep nodes, and I > often have to query if a node is "in path" of another node. > > Is there a good solution to build directory-tree like datastruktures? > I found, http://www.sai.msu.su/~megera/postgres/gist/ltree/ which seems > to do what i want, but I've no idea (and probalbly no chance) to get > that running on my system ;-( > > Thanks, > AXEL. > > > ---------------------------(end of broadcast)--------------------------- > TIP 3: if posting/reading through Usenet, please send an appropriate > subscribe-nomail command to majordomo@postgresql.org so that your > message can get through to the mailing list cleanly >
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