W3C home > Mailing lists > Public > www-zig@w3.org > December 2002

Re: Version 1.0 of SRW and CQL

From: Archie Warnock <warnock@awcubed.com>
Date: Mon, 2 Dec 2002 10:47:42 -0500
Message-ID: <028001c29a1a$26fa24b0$0901a8c0@pommard>
To: <www-zig@w3.org>

----- Original Message -----
From: "Eliot Christian" <echristi@usgs.gov>
> >Relations are more difficult as they require changing the CQL spec.  We
> >did discuss GEO relations during the CQL discussions but decided that as
> >none of us were experts we should leave it to the geospatial community to
> >tell us what their needs are in this regard
> I suspect that few people in the Geo community bother to track the ZIG
> list.

Well, I do, but I don't recall the discussion.  Perhaps it occurred during
the time that I was off-list.

Besides, there's a difference between syntax and semantics, except that
semantics are useless if the syntax doesn't permit them.  That is to say,
leaving discussion of relations to the geospatial community is fine as long
as CQL syntax permits them to be specified at all.  I just didn't see any
way to generalize the relations beyond those given in the CQL spec, which
really limits its utility.  Is that intentional?

We have a similar issue for structure attributes - those are used in GEO,
too (it's useful to distinguish between a single date and a date range, for

----- Original Message -----
From: "Adam Dickmeiss" <adam@indexdata.dk>
> > >[...] Mike Taylor I believe already has a CQL library in Java that
> > >converts the CQL format into the equivalent PQN for building gateways.
> >
> > That's good but to enable use of SRW/SRU I think we need agreements and
> > tools for making CQL out of arbitrary PQN, don't we? (Noting that PQN
> > itself directly translates from/to Z39.50 query structures.)
> Converting from CQL to Type-1 is difficult, due to a few "missing"
> attributes in Bib-1: Right anchor (last position in field),
> CQL masking for terms, etc.
> Converting from Type-1 to CQL is currently impossible. CQL simply doesn't
> carry attribute types and attribute values.

It would sure be handy for assisting the migration process to CQL.


-- Archie Warnock                   warnock@awcubed.com
-- A/WWW Enterprises                http://www.awcubed.com
--    As a matter of fact, I _do_ speak for my employer.
Received on Monday, 2 December 2002 10:47:44 UTC

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