[Koha] Use and possible removal of Keyword to MARC mapping config

[Ere Maijala]

Hi All,

So this became a bit long-winded but please bear with me...

I'm working on bug 11529 with the intention to add some of the most 
often required fields to the biblio table for quick retrieval. These are 
the current candidates: subtitle, medium, part number and part name. The 
reason for adding these is that they're often needed for proper 
identification of a work e.g. in the holds queue. The contents would be 
determined by the default framework like it's done in all the other 
fields too.

In current Koha versions only subtitle is available [1], but it is 
always retrieved from the MARC record, which slow especially if it's 
something like borrowers checkouts list that can have hundreds of elements.

The retrieval of subtitle from the MARC record is currently based on the 
"Keyword to MARC mapping" configuration in Koha. This has two 
differences compared to the proposed method of storing the fields in the 
biblio table according to the framework:

1. Since the default framework is now authoritative, all record follow 
it regardless of their selected framework.

2. Changes to the field mappings in the framework require a batch job to 
be executed on the server so that the changes are reflected in the UI.


What I've done so far builds on the idea that we could get rid of 
"Keyword to MARC mapping" (fieldmapping table) and rely solely on the 
framework and stored fields like is done for all the other fields 
(title, author, unititle, notes, series etc.). This idea, though, is 
based on the assumption that a single set of rules is enough and that 
the rules don't change often.

It would certainly be possible to support both ways of retrieving the 
subtitle, but it would make the code much more cumbersome. That's why 
I'd rather standardise on one way to do it.

So, any objections? :)

Regards,
Ere


[1] There have been 'numbers' and 'parts' also for the holds queue, but 
they haven't been exposed in the UI.

-- 
Ere Maijala
Kansalliskirjasto / The National Library of Finland