LISTSERV mailing list manager LISTSERV 16.0

Help for ZNG Archives


ZNG Archives

ZNG Archives


[email protected]


View:

Message:

[

First

|

Previous

|

Next

|

Last

]

By Topic:

[

First

|

Previous

|

Next

|

Last

]

By Author:

[

First

|

Previous

|

Next

|

Last

]

Font:

Proportional Font

LISTSERV Archives

LISTSERV Archives

ZNG Home

ZNG Home

ZNG  December 2004

ZNG December 2004

Subject:

Re: CQL implementation details

From:

Dr Robert Sanderson <[log in to unmask]>

Reply-To:

Z39.50 Next-Generation Initiative

Date:

Mon, 13 Dec 2004 22:01:57 +0000

Content-Type:

TEXT/PLAIN

Parts/Attachments:

Parts/Attachments

TEXT/PLAIN (96 lines)

On Mon, 13 Dec 2004, Mike Taylor wrote:
>> From: Hedzer Westra <[log in to unmask]>

>> Then, is there any difference between
>> a. idx = term1, and
>> b. idx =/cql.string term1
>> where term1 only contains 1 word
>
> Yes, absolutely!  The former would find records where idx has the
> value "term0 term1 term2", but the latter wouldn't.

Because string (and exact) assume that the term is anchored at both ends.

foo =/string "* word *"
foo =/word "word"

Would work the same, so long as the server splits words only by
whitespace, and 'word' doesn't appear with following punctuation. (etcetc)
These exceptions are why we need the word/string distinction, and why it's
important that the term in the query is processed the same as the data
from the records.


>> The context set currently defines five 'data types' (word, string,
>> number, isoDate, uri). Should all terms be assigned exactly one of
>> those?
>
> Hoo, that's a tricky one!
>
> I offer this the following "answer" for discussion, not as a
> definitive statement: I think the way to think about this is that
> "string" and "word" structures are fundamentally different from each
> other in that the former should not be broken into words, and the
> latter should.  The others seems to me to be either subtypes, or
> orthogal to this key dichotomy.  More likely the latter: one can
> imagine situations where you'd want to search only for an exact,
> complete, URI, and others where you want to do keyword searching on
> the URI (e.g. to discover all the URIs from a specified domain).

Wouldn't that be pattern matching, rather than keyword?  Unless you want
to split URIs up by / and then find foo in http://a.b.c/foo/bar ?
Secondly, if you do want to split URIs up by punctuation, you would search
as a keyword in an index of uris, not as a combined uri/word?

I think that they're all mutually exclusive, but that string is subclassed
into URI.  (everything that is true of string is true of URI, plus it has
a defined format)


>> Is there a distinction between terms that are *not* assigned any
>> type (either in the search query or by the server), and terms that
>> are typed 'string' (except for multi-word '=' searches without any
>> modifiers?)
>
> "exact" induces the "word" structure (unless overridden by an explicit
> relation modifier).  Similarly, "=" induces the "string" structure
> (unless overridden by an explicit relation modifier).  A better
> question would be this: what structure should "<" and the other
> inequality relations induce on their terms?

Other way round, Mike :)  Exact has a default of string, = is word unless
the server thinks that it should be numeric equality. (eg if the term is
numeric and the index is numeric)


>>> To expand upon Mike's typical one-liner, the problem is that then
>>> you have to include the entire search clause

>>> (or attribute combination for Z) and the only thing that you can
>>> search by are indexes, rather than relatively arbitrary data.  I'm
>>> not (personally) averse to reworking the sort definition for 1.2,
>>> so if you have any concrete ideas, put them forwards :)

I think this is worth expanding upon, in light of the above discussion.

If you want to sort by a numeric index alphabetically, rather than
numerically, then you need to know more than just the index, you need to
have the index and relation/relationModifier.

Of course, we can't do that now either, and we have problems with
namespace resolution in the XPath.  So to be a little less vague, when I
say that I'm not averse, it's more that I in fact think the sort
definition needs completely overhauling, but that's a lot of stuff to
think about right before the holidays and didn't think that anyone else
would care :)


Rob

       ,'/:.          Dr Robert Sanderson ([log in to unmask])
     ,'-/::::.        http://www.o-r-g.org/~azaroth/
   ,'--/::(@)::.      Dept. of Computer Science, Room 805
,'---/::::::::::.    University of Liverpool
____/:::::::::::::.  L5R Shop: http://www.cardsnotwords.com/
I L L U M I N A T I

Top of Message | Previous Page | Permalink

Advanced Options


Options

Log In

Log In

Get Password

Get Password


Search Archives

Search Archives


Subscribe or Unsubscribe

Subscribe or Unsubscribe


Archives

July 2017
October 2016
July 2016
August 2014
February 2014
December 2013
November 2013
October 2013
February 2013
January 2013
October 2012
August 2012
April 2012
January 2012
October 2011
May 2011
April 2011
November 2010
October 2010
September 2010
July 2010
June 2010
May 2010
April 2010
March 2010
February 2010
January 2010
December 2009
October 2009
September 2009
August 2009
July 2009
May 2009
April 2009
March 2009
February 2009
December 2008
November 2008
October 2008
September 2008
August 2008
July 2008
June 2008
May 2008
April 2008
March 2008
February 2008
January 2008
December 2007
November 2007
October 2007
September 2007
August 2007
July 2007
June 2007
May 2007
April 2007
March 2007
January 2007
December 2006
November 2006
October 2006
September 2006
August 2006
July 2006
June 2006
May 2006
April 2006
March 2006
February 2006
January 2006
December 2005
November 2005
October 2005
September 2005
August 2005
July 2005
June 2005
May 2005
April 2005
March 2005
February 2005
January 2005
December 2004
November 2004
October 2004
September 2004
August 2004
July 2004
June 2004
May 2004
April 2004
March 2004
February 2004
January 2004
December 2003
November 2003
October 2003
September 2003
August 2003
July 2003
June 2003
May 2003
April 2003
March 2003
February 2003
January 2003
December 2002
November 2002
October 2002
September 2002
August 2002
July 2002
June 2002
May 2002
April 2002
March 2002
February 2002
January 2002
December 2001
November 2001
October 2001
September 2001
August 2001
July 2001

ATOM RSS1 RSS2



LISTSERV.LOC.GOV

CataList Email List Search Powered by the LISTSERV Email List Manager