Re: Is this the most efficent way to child nodes off a N-ary
| От | Oleg Bartunov |
|---|---|
| Тема | Re: Is this the most efficent way to child nodes off a N-ary |
| Дата | |
| Msg-id | Pine.GSO.4.44.0202142236330.9731-100000@ra.sai.msu.su обсуждение исходный текст |
| Ответ на | Is this the most efficent way to child nodes off a N-ary node database? ("Christian Brink" <cb@onsitetech.com>) |
| Список | pgsql-sql |
Christian, take a look at our contrib/tree module, available from http://www.sai.msu.su/~megera/postgres/gist/ Oleg On Thu, 14 Feb 2002, Christian Brink wrote: > I have created this SQL statment, used to pull the child/leaf nodes off of a > N-ary node structure in PostgreSQL. > > Is my premise all wrong? > > Is this efficent as a SQL select? > > Should this be done in my code (something I try to avoid for abstraction > reasons)? > > "SELECT DISTINCT t1.node_id FROM node t1 WHERE NOT EXISTS (SELECT > t1.node_id FROM node t2 WHERE t1.node_id = t2.parent_id);" > > > > > ---------------------------(end of broadcast)--------------------------- > TIP 2: you can get off all lists at once with the unregister command > (send "unregister YourEmailAddressHere" to majordomo@postgresql.org) > Regards, Oleg _____________________________________________________________ Oleg Bartunov, sci.researcher, hostmaster of AstroNet, Sternberg Astronomical Institute, Moscow University (Russia) Internet: oleg@sai.msu.su, http://www.sai.msu.su/~megera/ phone: +007(095)939-16-83, +007(095)939-23-83
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