>> Is anybody else thinking about the limits of SQL? As often I am probably
>> not the first to ask these questions. Any pointers?
>
> Joe Celko (sp?) has a couple of books on this subject, SQL for Smarties. I
> don't recall if he talks about graphs, but does discuss queries on tree
> relationships.
I've got the 2nd edition and while I haven't made it that far, Ch 30 is on
graphs.
-philip