[ZOOM] Possible new Connection properites - comments?

Alan Kent ajk at mds.rmit.edu.au
Tue May 25 01:54:03 CEST 2004

Moving this over to the explain list - its nothing to do with ZOOM any more.

On Mon, May 24, 2004 at 05:08:43PM +0100, Rob Sanderson wrote:
> > 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:
> Right.
> 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.

Oh. Does that mean I cannot use it to describe the CCL names supported
by the database? (I have a server that does support native CCL queries
that use the name but does not support native CQL queries.) <map>/<name>
now means CQL index name (but without a prefix and URI) and not a CCL
index name.

Maybe this is really a sign that things are not quite right here with
ZeeRex. E.g. maybe the <name> element should have an element saying
what sort of name it is (CQL, CCL, the default being CQL if you like).

> > 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"/>
> 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.

Do you both therefore believe that I should not use ZeeRex at all for
this purpose? That is not use ZeeRex to describe a Z39.50 server in
terms of attribute lists, with information about how to translate CQL
and CCL queries into RPN for that server? Or just that I should not use
the <map>/<name> element for this purpose and use my own namespaced
element instead?

Note that providing a way for clients to dynamically discover a set of
recommended names for accessing a Z39.50 server for uses such as CCL,
CQL, GUI interfaces with drop down lists of choices etc I remembered
as being on of the original major goals of ZeeRex. Its the one thing
that classic Explain failed to do.

So, unless I get other suggestions, I think I will stop using <map>/<name>
and use a private namespaced element within a ZeeRex record. My reason
for doing this is I think using ZeeRex for various projects may be
of interest for possible ZeeRex extensions in the future. Nothing like
trying something out in practice before proposing a change to a standard.


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