From: Assaph Mehr <assaph@...>
Date: 2005-10-24T14:04:50+09:00
Subject: Re: Madeleine, SQLite and multi-platform issues (in ruby :-)

> >So how are many-to-many relationshops handled (e.g. authors and books)?
> >
> Hmm, let me think about this.  I guess I would create an author table, a
> book table, and a book_author table in the middle that would link the
> two.  I think that would work for a many-to-many.

Sounds like standard practice to my (inexperienced) mind. I was just
wondering if there was something like the ActiveRecord
#has_and_belong_to_many magic.


> >Also, how well does KB deal with "schema" changes between revisions? I
> >mean a new class version vs old data-store - how do I handle old
> >record data vs. new fields?
> >
> >
> You are free to modify the record class as much as you want.  KirbyBase
> is going to pass in the field values to the #kb_create method.  After
> that, it is up to you to do with them what you will.

OK, here's a specific example.:

Suppose I had Foo with two fields :bar and :baz. The #kb_create had
those as parameters and KB passed them in as needed.

Now version 2 has the same class Foo, but with the fields :baz and
:qux. I.e. one field was deleted and another was added. Their relative
'position' in the method arguments has also changed. Now if I send my
shiny new v2.0 to a user who has a smelly old v1 database, what will
happen? What do I need to do to respond, recover and/or upgrade the
existing database?


Cheers,
Assaph