[Zope3-Users] zodb and object updating

[Pete Taylor]

That's exactly what I was looking for.  after googling for
"generations" I found another request for the same thing in early Feb
this year.  My fault for not finding it before ;)  Thanks for pointing
me in the right direction.


> On 3/17/06, Chris Withers <chris at simplistix.co.uk> wrote:
> > Isn't this what the "generations" code is for?
> >
> > cheers,
> >
> > Chris
> >
> > Pete Taylor wrote:
> > > Hi all,
> > > I've run into an interesting issue.  I've been building an application
> > > in zope3 over the last few months to meet a business need where I
> > > work.  Basically just capturing a lot of data about prospective
> > > insurance agencies, creating applications for them, pdfing them
> > > (reportlab rocks), and emailing the responsible parties, archiving the
> > > applications, etc.
> > >
> > > the issue is though that as the business community comes back to me
> > > with changes, there are cases where the object design itself needs to
> > > be modified.  Things that were Textline's need to be Lists, etc, as
> > > they determine that they would like to capture extra values for
> > > similar data, and what have you.
> > >
> > > obviously it's not a problem for just modifying the objects for all of
> > > them going forward, but for all old data and archived applications, I
> > > need to update the old objects to fit the new interfaces.  as an
> > > example, the original design spec only allowed for one agency owner.
> > > it was a Textline.  they then asked to be able to have multiple
> > > owners, in the case of a partnership.  I would, of course, then change
> > > "owner" to "owners" and make it a List, and modify the relevant bits
> > > in the rest of the code.  but all the old applications will just have
> > > a single "owner" Textline as that particular attribute for the class.
> > > I need to be able to go through the old applications, find all
> > > instances of "owner", create "owners" in the stored object, and make
> > > the original "owner" a single element in the new list.
> > >
> > > my issue is how to do this offline in the zodb.  I've read through the
> > > posts I can find on manipulating the zodb, but I haven't really
> > > "gotten" it, and a lot of what i can find is zope2 stuff...  my
> > > knowledge of the zodb isn't extensive, so the zope2 info may still be
> > > good?
> > >
> > > if anyone has links or recommendations on where to look to start doing
> > > this kind of thing, that would be excellent, as would any advice on
> > > do's and don't's.  as this application lives in our environment,
> > > changes to the design will inevitably create this issue time and
> > > again, so I'd like to know how to confront changes like this in a
> > > workable way.
> > >
> > > Thanks!
> > >
> > > --
> > > "All guilt is relative, loyalty counts, and never let your conscience
> > > be your guide."
> > >   - Lucas Buck, American Gothic
> > > _______________________________________________
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> > > Zope3-users at zope.org
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> > >
> >
> > --
> > Simplistix - Content Management, Zope & Python Consulting
> >             - http://www.simplistix.co.uk
> >
>
>
> --
> "All guilt is relative, loyalty counts, and never let your conscience
> be your guide."
>   - Lucas Buck, American Gothic
>


--
"All guilt is relative, loyalty counts, and never let your conscience
be your guide."
  - Lucas Buck, American Gothic