Re: query that Bob is descendant of Alice

In article <9bsksm$p76$06$1_at_news.t-online.com>, Carl Rosenberger <carl_at_db4o.com> wrote:
>Robert Vazan wrote.
>> I think SQL can express only static depth of links:
>
>No, this is not true, but you need a lot of SQL experience to construct
>something decent.
>
>> 1. Can this be done? (practically)
>
>Anything can be done.
>It is only a matter of effort.

Ah. Please, sir, will you write something to tell me if an abitrary Turing machine will halt?

More seriously, the question of whether A can call B is insoluble in general. For languages without the concept of a function address variable (e.g. Fortran 77 and not C), it is trivial to produce a generally useful bound. Whether SQL is the way to analyse such data is beyond my knowledge ....

Regards,
Nick Maclaren,
University of Cambridge Computing Service, New Museums Site, Pembroke Street, Cambridge CB2 3QG, England. Email: nmm1_at_cam.ac.uk
Tel.: +44 1223 334761 Fax: +44 1223 334679 Received on Sun Apr 22 2001 - 02:55:24 CDT