[ZOOM] Possible new Connection properites - comments?

Robert Sanderson azaroth at liverpool.ac.uk
Mon May 24 18:08:43 CEST 2004

On Mon, 24 May 2004, Mike Taylor wrote:
> > From: Alan Kent <ajk at mds.rmit.edu.au>

> > > Unless I am missing something, this is not ZeeRex; merely an XML
> > > format that resembles it in every syntactic respect.  Sorry.
> > I should stop mailing I know

> Actually as I read the ZeeRex DTD Commentary at
> 	http://explain.z3950.org/dtd/commentary.html#5.3
> the first of these two <map>s _is_ CQL-specific:

It used to be for complex attributes, but as was pointed out, you can 
describe them still using <attr> maps, no need for a special case.  So for 
2.X they became only CQL.

> One solution to this problem would be to add a new element in ZeeRex
> 2.1, that really does mean what you want:
> 	    <applicationsMayTranslateThisCQLIndexIntoThisMap name="title"/>

Well, surely:
<applicationMayTranslate set="dc" name="title"/>

But then you also need to define which set 'dc' refers to, so you'd need:
<applicationShouldKnowShortName set="dc" identifier="info:srw/..."/>

Of course, you would also want to map back the other way...

<applicationMayTranslate protocol="Z39.50" version="3">
  <attr set="xd" type="1"> ... </attr>
  <attr set="bib2" ... </attr>

And if they don't support the attribute architecture you'd also want to 
give the BIB1 form(s).

Then you might also want to say which SQL table you're storing the index 
data in, so ...

No! Make it stop!

> Now you will say that in Real Life, that's exactly what's needed
> because different servers do behave differently.  One accepts @attr
> 1=1003 for author searches, but another can't do that and needs to be
> sent @attr 1=1.  "I feel your pain".

Shouldn't this global map have options?
dc.creator is:  1=1
                1=3179  (or whatever dc.creator is)

And then the application can decide which one to use based on the ZeeRex 
files that say which are available.

> Problem is, if we add this element, I bet you a billion dollars (US)
> that everyone will stuff their ZeeRex records to the gills with dozens
> of redundant <applicationsMayTranslateThisCQLIndexIntoThisMap> elements.

Yes. And everyone else will be confused as to why a service description 
for Z39.50 has application specific information for use by other services.

Why should my Z39.50 server care what your application calls an attribute 
combination internally? The server never sees that name. You could call it 
fish.troutsArePink for all the server cares, so long as the RPN received 
is standard.

A comprehensive global mapping between RPN (various flavours) and CQL 
would be very useful, but I don't think that ZeeRex is the place to do it.


      ,'/:.          Dr Robert Sanderson (azaroth at liverpool.ac.uk)
    ,'-/::::.        http://www.o-r-g.org/~azaroth/
  ,'--/::(@)::.      Special Collections and Archives, extension 3142
,'---/::::::::::.    University of Liverpool
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