Ron Peterson writes:
> The problem is, while it's easy enough to define such a data
> structure, support for recursive queries is rather lacking. To unroll
> a directory tree, you basically have to resort to programming in
> <insert your favorite language>.
Well, nothing is perfect, and this is exactly the point where relational
databases aren't. A lot of people that are a lot more educated than me on
the matter have commented on just this in detail for years and decades so
you should be able to find enough material out there if you're interested.
Apparently, this sort of thing worked in network and/or hierarchical
databases (which came before relational) and object oriented databases are
supposes to fix it again, but the fact that all the world uses relational
databases shows that either recursion (infinite joins) isn't widely useful
or that the other advantages outweigh this problem. Not sure.
--
Peter Eisentraut Sernanders väg 10:115
peter_e@gmx.net 75262 Uppsala
http://yi.org/peter-e/ Sweden