Re: (FAQ?) JOIN condition - 'WHERE NULL = NULL'

["Ian Sillitoe" <ian.sillitoe@xxxxxxxxxxxxxx>]

Thanks very much for this and to all the reponses. As a side note, I've only joined this mailing list this afternoon, but it already seems like an good choice (albeit one I should have made about 2 years ago :P) - very active and very helpful - excellent work, many thanks indeed.

Cheers,

Ian

On Wed, Apr 2, 2008 at 8:08 PM, Richard Broersma <richard.broersma@xxxxxxxxx> wrote:

On Wed, Apr 2, 2008 at 11:43 AM, Ian Sillitoe
<ian.sillitoe@xxxxxxxxxxxxxx> wrote:
> I completely take your points - so maybe I should be asking for advice on
> database design instead.

There are a couple of choice you can use:

First is the PostgreSQL contribe Module Ltree:
http://www.postgresql.org/docs/current/static/ltree.html

There is the common adjancy list model:
http://www.sqlsummit.com/AdjacencyList.htm

Celko's Nested set model: { probably provides the most functionality
but with hi costs for INSERT/UPDATE ops)
http://www.intelligententerprise.com/001020/celko.jhtml

and Lastly the Path enurmation model:
http://www.onlamp.com/pub/a/onlamp/2004/08/05/hierarchical_sql.html

One of these model should hopefully be a best fit for you.

--
Regards,
Richard Broersma Jr.