Hi Ray,

One person at the NISO meeting suggested that you should be able to send
different queries to different logical databases.. however, I'm not at all
sure that this requirement is universal, and it would seem to me to add
unnecessary complexity.

Otherwise the main complexity compared to vanilla Z39.50 is that I'm pretty
sure the metasearch agent, in some cases, is going to want individual hit
counts *and* access to the separate "sub result sets" of records from each
database. Sometimes you may want to use the server's facilities for sorting
and possibly deduplication, but in other cases, the metasearcher is sure to
be able to display individual record lists for each database.

--Sebastian

At 07:50 27-05-2003 -0400, Ray Denenberg wrote:
>Sebastian Hammer wrote:
>
> > The question is whether we can specify a sufficiently powerful
> > multi-database mechanism without throwing the simplicity of the protocol
> > overboard.
>
>Is it really so complicated?
>
>We would need a databaseName parameter (optional, repeatable) in the query,
>databaseName element in <RecordData> within <record> in
><searchRetrieveResponse>
>and some hit count information.
>
>And semantics.  But the semantics are well-developed for Z39.50, and would
>be much
>simpler in an SRW context. They could be extracted/modified from:
>http://lcweb.loc.gov/z3950/agency/wisdom/pdu-multi-db-support.html, and
>http://lcweb.loc.gov/z3950/agency/clarify/db-status.html
>or look at:
>http://www.niso.org/standards/resources/Z39-50-200x.pdf
>3.2.2.1.2 "2. Multi Database searching" and 3.2.2.1.7  "When query is not
>supported for a database", etc.
>
>--Ray

--
Sebastian Hammer, Index Data <http://www.indexdata.dk/>
Ph: +45 3341 0100, Fax: +45 3341 0101