[Koha] Question on Z39.50 cross-format queries

[Chris Cormack]

* Manos Petridis (egpetridis at yahoo.com) wrote:
> >________________________________
> > From: Robin Sheat <robin at catalyst.net.nz>
> >To: koha at lists.katipo.co.nz 
> >Sent: Tuesday, August 14, 2012 1:07 PM
> >Subject: Re: [Koha] Question on Z39.50 cross-format queries
> > 
> >
> >Op 13-08-12 21:36, Manos Petridis schreef:
> >> a) It it were simply a case of either/or, then why can I select the MARC flavour of the various Z39.50 origins set up at my installation? What is the reason to let koha know of the MARC flavour/dialect, if it not able to use the data that each server sends? There must be some functionality behind the dropbox selections, even if it only defines the query statement dialect.
> >
> >Koha needs to know what you are using, so that it knows what field to
> >pull from for the title, and how to index the title in zebra to make it
> >correctly searchable, for example. There are a number of other cases
> >where the differences are a bit deeper than just different field IDs.
> >
>  
> That's exactly my point! Koha knows 
> a) what MARC flavor my installation is using 
> b) what MARC form each Z39.50 origin accepts requests and supplies its results in
> It should therefore be able to know "what field to pull from for the title" etc. 
>  
> I would expect that zebra indexes the various koha tables, not the imported MARC records, i.e. works on data past the mapping phase.

Then you would be expecting wrong, it indexes the MARC, which is
stored as marcxml in the biblioitems table. If yuo want more in depth
on the internals of Koha, it's better on the koha-devel list.

Only a small fraction of the over 900 marc fields (most of which are
repeatable) and their myriad of subfields (also repeatable) are mapped
to columns in the database and stored. 

The cataloguers on this list will be able to tell you much better than
I, but a crosswalk between UNIMARC and MARC21 (or NORMARC, or DANMARC
or whatever else) is very hard to pull off, when you have to deal with
control fields, indicators etc

Chris
-- 
Chris Cormack
Catalyst IT Ltd.
+64 4 803 2238
PO Box 11-053, Manners St, Wellington 6142, New Zealand