[Koha-devel] about MARC format

[paul POULAIN]

This mail is primarily for Steve and continues an IRC conversation we 
had on friday, but I think it could interest other koha developers and 
readers of this ml.

The problem :
We have 2 problems with MARC-DB structure :
The 1st, which is solved, was that repeatable tags we not rightly stored 
in our structure : thus, it was hard to differenciate lines. The problem 
will be solved by adding a "tag number" field in the DB. Should be cvsed 
soon...
The 2nd, which is still to solve, is multiple-items support. We plan to 
support many MARC (MARC21, UNIMARC...) by having a parameter table. But 
the BIG problem is that koha "items" are managed completly differently 
in MARC21 and in UNIMARC. In fact, in true-UNIMARC they are not 
supported... In france, they are supported by a "almost-official" 
document, the "995 tag", which defines the 995 tag as the koha-item field.
So, when there are more than 1 item of a given biblio, how to manage 
them in MARC-DB. Quite impossible with actual DB structure.

I've had a simple idea during the we, which, I'm almost sure, is the 
best one :
In our MARC sructure, we have a old-DB-"biblio" field that links the old 
DB and the MARC one. We should add a "koha-item" field in the DB that 
links a old-DB item and a "MARC-item".
In the MARC-API, we should add a MARCadditem, MARCmoditem and 
MARCdelitem sub.

I'll try this very soon, unless someone (steve ?) points me an error.
--
Paul