Le 06/09/2011 19:23, Jared Camins-Esakov a écrit : > Hello. Hi, > > I was looking at the schema that Koha uses for its database, and noticed > a few peculiarities that I wonder if anyone could shed some light on: > > The serial table uses VARCHAR(100) for serial.biblionumber and > serial.subscriptionid.
> Is there any context in which those are not > numeric identifiers? I donot think so. They should indeed be INT or BIGINT. > Presumably as a result of that, there are no > foreign key constraints on the serial table. I think there probably > should be. you are right and even, serial.biblionumber should be removed from taht table since it is in subscription table. > > There's a similar situation with the subscription table: > subscription.biblionumber doesn't have a foreign key relation with > biblio.biblionumber, nor, indeed, any index at all. same here. > Foreign keys are > also lacking for subscription.aqbooksellerid and subscription.aqbudgetid. I think we (BibLibre) have some interesting ongoing work wich copes with serials acquisitions which could result in getting rid of that data. > > On the subject of foreign keys, should items.itype have a foreign key > linking it to itemtypes? Could be discussed. But items.itype was introduced in 3.0 in order to store itemtype in addition with ccode (circulation/collection code). I think that items.itype should stick to itemtype. But since it CAN be NULL sometimes when you donot use itemtypes, then creating a foreign key would be too much compelling. You surely would not like to see the data not stored silently because of a FK check fail on that data. Koha was meant to manage mandatory tags/subfields from the interface and not at a database level (from what I know of it). > > My understanding of foreign key relationships is that they're a Good > Thing because they provide a means to ensure referential integrity. Am I > missing something in these particular cases (and there are probably > others, these are just the ones I happened to notice), or would people > say this was probably just an oversight? > > Regards, Regards. -- Henri-Damien LAURENT _______________________________________________ Koha-devel mailing list [email protected] http://lists.koha-community.org/cgi-bin/mailman/listinfo/koha-devel website : http://www.koha-community.org/ git : http://git.koha-community.org/ bugs : http://bugs.koha-community.org/
