[Koha-devel] marc stuff

[paul POULAIN]

Tonnesen Steve wrote:

>On Thu, 16 May 2002, paul POULAIN wrote:
>
>And Canadians?  :)
>
In french, américains, means people from notrh-America (mexico, US, 
Canada) AND people from USA. so in my mind yu were included ;-)

>I have a Marc schema question for you Paul, if you're still around
>today...
>
>How do I store the following tag:
>
>100  a Dolch, Edward W.
>     q (Edward William),
>     d 1889-1961
>
>in marc_1XX_tag_table I'd put:
>   
>  bibcode=1234
>  tagnumber=100
>  tagorder=1
>  indicator=##
>  tagvalue=Dolch, Edward W.
>  valuebloblink=NULL
>
>I seem to be missing the subfield code, and I need a unique id for the
>record for editing purposes.  Did you intend to put a separate record in
>marc_1XX_tag_table for each subfield?  We'd also need some way to tie all
>the subfields of a given tag together.
>
You did'nt undestand my idea : in the 1XX_tag_table, you store the full 
line. So, the record looks :

bibcode=1234
  tagnumber=100
  tagorder=1
  indicator=##
  tagvalue=$aDolch, Edward W.$q(Edward William)$d 1889-1961
  valuebloblink=NULL

Don't forget that the tag_tables are used only for presentation purposes 
only. We search all with tag_word table.
We can split thit record with a simple regexp, to get more user-friendly 
presentation.
A regexp is FASTER than reading 10 or 15 records from the database. More 
than that, with your structure, we have to join 3 tables (biblio, 
tag_table, subfield_table) before getting any information. With my 
structure, we need only 2.
So, I think (no, in fact I'm sure ;-)) that we don't need a subfield_table.

About other modifications :
FROM :

 CREATE TABLE marc_biblio (
! 		bibcode bigint(20) unsigned NOT NULL auto_increment,
  		datecreated date NOT NULL default '0000-00-00',
TO :
  	CREATE TABLE marc_biblio (
! 		bibid bigint(20) unsigned NOT NULL auto_increment,
  		datecreated date NOT NULL default '0000-00-00',

I agree.

FROM :

  	CREATE TABLE marc_0XX_tag_table (
! 		bibcode bigint(20) NOT NULL default '0',
  		tagnumber char(3) NOT NULL default '',
  		tagorder tinyint(4) NOT NULL default '0',
  		indicator char(2) NOT NULL default '',
! 		tagvalue varchar(255) default NULL,
! 		valuebloblink bigint(20) default NULL,
! 		PRIMARY KEY  (bibcode,tagnumber,tagorder)
  		) TYPE=MyISAM;

TO :

  	CREATE TABLE marc_0XX_tag_table (
! 		tagid bigint(20) unsigned NOT NULL auto_increment,
! 		bibid bigint(20) NOT NULL default '0',
  		tagnumber char(3) NOT NULL default '',
  		tagorder tinyint(4) NOT NULL default '0',
  		indicator char(2) NOT NULL default '',
! 		PRIMARY KEY (tagid),
! 		KEY (bibid,tagnumber,tagorder)
  		) TYPE=MyISAM;

I STRONGLY DISAGREE !
Why ?
because (bibid,tagnumber,tagorder) IS A PRIMARY KEY. You can 
undoubtfully find a record with those three informations. So we don't 
need a auto_increment field that is redundant. It's a DB-design mistake. 
I'm (almost) sure it's a bad idea.
Note tagvalue and valuebloblink deseappear and should also re-appear if 
we drop subfields_table.


I won't be reachable before 4PM-GMT. I'll try to be on irc for a few 
moment at 4PM-GMT to speak with you about the structure. Hoping we will 
be able to reach a "definitive" structure.
--
Paul