Date:         Tue, 9 Dec 2003 16:13:39 GMT
Reply-To:     "Z39.50 Next-Generation Initiative" <[log in to unmask]>
Sender:       "Z39.50 Next-Generation Initiative" <[log in to unmask]>
From:         Mike Taylor <[log in to unmask]>
Subject:      Re: Attribute lists for queries - what are people doing?
Comments: To: [log in to unmask]
In-Reply-To:  <[log in to unmask]> (message from Robert Sanderson on Tue,
              9 Dec 2003 13:27:40 +0000)

> Date: Tue, 9 Dec 2003 13:27:40 +0000
> From: Robert Sanderson <[log in to unmask]>
>
> >     dc.title <>/stem monies
> > when using the Bib-1 attribute set would be an error (???).
>
> Unless you can turn the <> relation into a not boolean.

I am not convinced that a well-behaved implemetation has licence do
this.
        au=kernighan and ti <> unix
may be a subtly different query from
        au=kernighan not ti=unix

(Example: if the back-end works by querying an SQL database, the
latter query will find records with author=kernighan and title
undefined, whereas the former will not.)

> > Finally, exact, any, and all are interesting cases. There is no
> > 'any' in Bib-1 (unless I have an old printout). 'all' I guess is
> > 'word list'.

I don't think it was ever the intention to use "word list" for this.

I seem to remember there was a proposal to add explicit "any of these
words" and "all these words" attributes to the BIB-1 attribute set,
but I can't find any mention of them in
        http://lcweb.loc.gov/z3950/agency/defns/bib1.html#relation
Am I imagining things?  Or what happened to that proposal?

When using the attribute architecture, of course, there are
format/structure attributes for these concepts: @attr 9=3 and @attr
9=2 respectively.  Although that, too, was up in the air for a long
time, wasn't it?  Does what's current on the site at
        http://www.loc.gov/z3950/agency/attrarch/util.html
represent the outcome of that discussion, or did it run out of steam
so that what's there now is what was always there?

> For any, I turn the clause into a tree of OR clauses in bib1, AND
> clauses for all. Yes, this isn't quite correct, as the client will
> likely have different 'word' extraction to the server.

Yup.  I think we all agree that this is The Wrong Thing, but it seems
to be the right thing to do anyway :-)

 _/|_    _______________________________________________________________
/o ) \/  Mike Taylor  <[log in to unmask]>  http://www.miketaylor.org.uk
)_v__/\  "... about as similar as two completely dissimilar things
         in a pod" -- Black Adder.

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