Thanks. This is indeed the solution I have been pursuing. My intention is
to control the joins through a set of declarations (in XML :-) - this means
that they can be reconfigured by different people/clients. I wondered if
there was already a standard 'language' for this or whether I just hack my
own and hope.
P.
Peter Murray-Rust, Director Virtual School of Molecular Sciences, domestic
net connection
VSMS http://www.nottingham.ac.uk/vsms, Virtual Hyperglossary
http://www.venus.co.uk/vhg