sru and query

[David Loy-2]

I haven't been keeping up with the z39.50 list to know
if it deals with sru questions.

Is there any mechanism in sru (not srw) that allows
alternate query types to be used (e.g. Google, etc.)
instead of cql?

Thanks
David Loy

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[ray denenberg-2]

From: "David Loy" <de_loy@...>

> I haven't been keeping up with the z39.50 list to know
> if it deals with sru questions.

David - There is a listserv for SRU, see
http://www.loc.gov/standards/sru/listserv.html

> Is there any mechanism in sru (not srw) that allows
> alternate query types to be used (e.g. Google, etc.)
> instead of cql?

There is no SRU (nor SRW) analog to the Z39.50 query type.  (However there
is an "extra-data" parameter where you can stick a query.)

--Ray

[Mike Taylor-10]

> Date: Wed, 15 Feb 2006 08:55:39 -0800 (PST)
> From: David Loy <de_loy@...>
>
> Is there any mechanism in sru (not srw) that allows
> alternate query types to be used (e.g. Google, etc.)
> instead of cql?

Hi, David.  As Ray points out, it would be possible to use a profiled
SRU/W extension to do this.  But it's strongly discouraged, because
one of the great strengths of SRU is precisely that it has just one
query language.  Although it makes initial implementation a little
trickier(*), the result is that any query can be sent to any SRU
implementation, and that is a very big win especially for
metasearchers.

(*) I say "a little trickier" because, as you may know, there are
excellent free CQL parsers available, which you're welcome to use in
your project.  See
        http://zing.z3950.org/cql/
which links to parsers for Java, Python, C/C++, Perl and PHP.

... as it happens, I literally yesterday wrote a new section in the
manual for Index Data's SRU-compatible database engine, Zebra, which
says:

        NOTE: It is possible to cheat, by having SRU or SRW
        search Zebra with a PQF query instead of CQL, using
        the "x-pquery" parameter instead of "query".  This is
        a NON-STANDARD EXTENSION of CQL, and a VERY NAUGHTY
        thing to do.

So I am not proud of this.  We use it only as a debugging aid.

 _/|_ ___________________________________________________________________
/o ) \/  Mike Taylor  <mike@...>  http://www.miketaylor.org.uk
)_v__/\  Why do people say that Oasis are the New Beatles, but not that
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