On Apr 19, 2006, at 14:44 , Martin Kuria wrote:
I have a postgresql database Table Categories which has the
structure like this
Cat_ID | Parent_ID | Name
------------------------------------
1 | 0 | Automobiles
2 | 0 | Beauty & Health
3 | 1 | Bikes
4 | 1 | Cars
5 | 3 | Suzuki
6 | 3 | Yamaha
7 | 0 | Clothes
According to the above Database data, Suzuki and Yamaha are the
Subcategories of Category Bikes and Bikes in turn is the
Subcategory of Automobiles.
If you're looking at having a potentially deep hierarchy, I'd
recommend taking a look at nested sets, which also allows you to keep
everything in one table.
http://www.intelligententerprise.com/001020/celko.jhtml?
_requestid=145525]
By the way, the method you outline above is often called the
adjacency list model.
Hope this helps.
Michael Glaesemann
grzm myrealbox com
---------------------------(end of broadcast)---------------------------
TIP 9: In versions below 8.0, the planner will ignore your desire to
choose an index scan if your joining column's datatypes do not
match
