[Koha] Ramblings on a Catalogue API

[Tonnesen Steve]

More technical mumbo jumbo.

I'm thinking the new Catalogue API should have two interfaces: one that is
modelled on the biblio,biblioitems,items table and one that is modeled on
the MARC data.  Here are my ramblings on the first interface, which would
need to be implemented first anyway.



Adding a new item:


Create a $item object:

$item->{'biblioitemnumber'}=xxxx;
$item->{'barcode'}=xxxxx;
.
.
.
dateaccessioned=xxxxx;
booksellerid=xxxxxx;
homebranch=xxxxxxx;
price=
replacementprice=
replacementpricedate=
notforloan=
restricted=
holdingbranch=
itemnotes=


Call Catalogue->AddItem($env, $item)


The AddItem subroutine can insert the data into a new items record as
before, as well as:

Grab the MARC Record_ID number from the biblioitems table for
biblioitemnumber given in the $item object and add an 852 tag for the new
item in the MARC record.  We still have to work out where in the 852 tag
the different bits of information will be stored, or if some information
maybe should be stored elsewhere, like in 859 (any tag, subfield, or
indicator with a 9 in it is a local implementation).


Catalogue->UpdateItem($env, $item)

could be used to modify an existing item.  The $item object in this case
would also have to have an itemnumber.  The MARC side could grab the
barcode from the items table to find the corresponding 852 entry in the
MARC record.



Catalogue->AddBiblioitem($env, $biblioitem)

$biblioitem->{'biblionumber'}=xxxx;
volume=
number=
classification=
itemtype=
isbn=
dewey=
subclass=
etc.



Again, this would add an entry to the biblioitems table, and create a new
MARC record.  The Record_ID value from the newly created MARC record would
also be inserted into the new biblioitems record in a new Record_ID field.


Catalogue->UpdateBiblioitem($env, $biblioitem)

Same idea as UpdateItem...


Catalogue->AddBiblio($env, $biblio)
Catalogue->UpdateBiblio($env, $biblio)

These two subroutines have no counterpart in the MARC side.  The data
contained in the biblio table is stored in the MARC record for each of the
corresponding biblioitems.  All of the MARC records associated with a
given biblio would have a unique id (same as the biblionumber) stored
somewhere in the MARC record, location still to be determined. 


I'm not sure at the moment how many places in the existing Koha code will
have to be modified to use this new API.  All over the acquisitions code,
for sure, as well as the catalogue editing code.  Any other places that
need looking at?  Any spots in the code where updates may not fit with my
proposed API here?






Reading subroutines would be similar to the writing subroutines:

Catalogue->GetBiblio($env, $biblionumber);
Catalogue->GetBiblioitem($env, $biblioitemnumber);
Catalogue->GetItem($env, $itemnumber);


something like that.  These three subroutines would _always_ read from the
MARC record data.  This will be more difficult than the current setup
which just grabs the entire row from an SQL select statement and returns
the result as the object, but it ensures that there is a single
authoritative data source and allows for the eventual removal of the
biblio, biblioitems and items tables once their functionality is
completely met by the MARC records. 

These subroutines, specifically the GetBiblioitem and GetItem would also
return some structured MARC data: 1: a full MARC record, 2: a text
structured MARC record, 3: an HTML formatted MARC record.


Steve.