Remember, guys, that you have an "intelligent" MSE sitting in the middle
here. All of Rob's problem areas are part of daily life and we have ways of
dealing with them within the MSE. (Note carefully put - not 'solutions', but
'ways of dealing with'.) The issue of sending instructions to the MSE (for
the MSE to do processing) is a little more tricky and error conditions will
definitely expand. However a lot of the problems with result data can be
handled within a suitable data structure either agreed or extended (extra
result data). The above is why I thought a set of 'x-mse-????' extensions
could be the best way to go. Mike's "...database=abc+def+geh..." is a nice
extensible and invisible enhancement, but it does only address one dimension
of the problem - admittedly the biggest and the only one I raised in the
first place. There is obviously no absolute requirement to enable this sort
of communication within SRU/W and possible a MSRU/W (MetaSRU/W) wrapper may
be the sensible way to approach it.

Peter

> -----Original Message-----
> From: Z39.50 Next-Generation Initiative [mailto:[log in to unmask]]On Behalf Of
> Mike Taylor
> Sent: Thursday, June 16, 2005 11:15 AM
> To: [log in to unmask]
> Subject: Re: Betr.: Re: Multiple Sources in SRU/W
>
>
> > Date: Thu, 16 Jun 2005 17:55:02 +0100
> > From: Dr Robert Sanderson <[log in to unmask]>
> >
> >>> I disagree.  The amount of complexity in Z39.50 for searching
> >>> multiple databases at once was a serious impediment to
> >>> implementation, and the same will apply to SRW.
> >>
> >> What extra complexity?  Extend the database-name syntax to allow
> >> lists, add a what-database-the-record-is-from element to the result
> >> record, bam, you're done.
> >
> > Explain?
>
> Explain the virtual union DB.  Say nothing about the sub-DBs.  If you
> want to know about them, you can ask them for _their_ explain records;
> but of course you _don't_ want to know about them: avoiding such
> details is precisely why you're searching the union in the first place.
>
> > Scan?
>
> Same.
>
> > Databases that don't have common record schemas?
>
> Don't Do That, Then.
>
> > Databases without common indexes?
>
> Don't Do That, Then.
>
> > Databases without common (insert favourite SRW functionality here) ?
>
> Don't Do That, Then.
>
> etc.
>
>  _/|_
> ___________________________________________________________________
> /o ) \/  Mike Taylor  <[log in to unmask]>
http://www.miketaylor.org.uk
)_v__/\  ``SAY IT WITH CHEESE'' -- sign outside Dimock, South Dakota.

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