recursion - Mailing list pgsql-sql

From Julien Cadiou
Subject recursion
Date
Msg-id 3.0.3.32.19991125121554.010b4d80@mail.vicnet.net.au
Whole thread Raw
List pgsql-sql
Hi,


I'm trying to get my head around a simple problem but can't get it unless I expect too much of SQL/not enough of
myself...

I'm building a links indexing application and want to maintain full relationality in the database. My categories table
isas follows:
 

id|name                |owner

--+--------------------+-----
1|Leisure             |    0
2|Business            |    0
5|Men's tennis lessons|    7
4|Finance             |    2

10|Banks               |    4
6|Stock Market        |    4
8|Outdoors            |    0
7|Men's Tennis        |    3
9|Racket Sports       |    3
3|Sports              |    8


Each category has an id, a name and an owner. Subcategories are owned by other categories (the owner's id being the
ownervalue) etc ... which is the relation between id and owner.
 

By knowing, for example, the primary key of Men's tennis lessons (5), I want to extract all categories in its path, all
theway to the top, so as to get, in this case:
 

Outdoors > Sports > Men's Tennis > Men's Tennis Lessons


It seems to be a simple thing but after many joins and attempts at recursions, I still can't find it ...

I want to avoid multiple queries ...

Any ideas ? Thanks...



<bold>Julien CADIOU

</bold>Database Administrator

<bold>VICNET</bold> - Victoria's network
Phone: (03) 9669 9710
Fax:    (03) 9669 9805
Web:    http://www.vicnet.net.au/




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