Re: [Modeling-users] Foreign Keys

[Sebastien B. <sbi...@us...>]

        Hi,

Yannick Gingras <yan...@sa...> wrote:
> Hi, I'd like to set my foreign keys by hand ex.:
>=20
>   i18n =3D I18N()
>   ec.insert(i18n)
>   i18n.setMasterId(masterSnapshot["id"])
>   ec.saveChanges()
>=20
> Is there a way to do it without breaking anything ?
>=20
> Since I switched to raw fetches, I end-up with a dict that is unusable wi=
th=20
> addObjectToBothSidesOfRelationship().  In fact, having=20
> addObjectToBothSidesOfRelationship() accept snapshots would be nice.

First, a general answer to this.

  As said at http://modeling.sf.net/UserGuide/ec-fetch-raw-rows.html,
  when you use raw row fetching you forego most of the capabilities of
  the framework. This includes tracking changes (no objects are even
  created, so the framework cannot keep track of the changes), all the
  more so manipulating relationships and saving the changes.

  I should probably make it even clearer in the documentation.

  So what? Fortunately you're not stuck. In general, you have two
  solutions at hand:
=20=20
    - either fall back to raw sql. Probably not what you want...
=20=20
    - or revert the row you want to change into a real object, using
      EC.faultForRawRow(), then make your changes and save them.


Now back to your specific problem: based on your code, I assume you have
the following model:

    master <--->> i18n  (-> is to-one, ->> is to-many)

So you'll do something like this, assuming that the master entity's name
is 'Master' and the relationship' name i18n--->>master is: 'master'
and the inverse is 'i18ns':

>>> i18n =3D I18N()
>>> ec.insert(i18n)
>>> master=3Dec.faultForRawRow(masterSnapshot, 'Master')
>>> i18n.addObjectToBothSidesOfRelationshipWithKey(master, 'master')
>>> ec.saveChanges()

or its alternate equivalent:

>>> i18n =3D I18N()
>>> ec.insert(i18n)
>>> master=3Dec.faultForRawRow(masterSnapshot)
>>> master.addToI18ns(i18n)
>>> i18n.setMaster(master)
>>> ec.saveChanges()


  Naturally, this implies that the 'master' object is fetched and
  initialized within the EditingContext.

    Does it fulfill your needs?

-- S=E9bastien.