Noob ? - Foreign Key


#1

I am attempting to use scaffolding to create a simple foreign key
example. But I am not quite understanding how rails writes data into
the foreign table. When the “belongs_to” and “has_many” lines are
added into model, will rails automatically add the information into
the foreign table? Or do I have to modify the controller to insert
the data into the foreign table? Could someone give me an example. I
would like the data in the foreign table not to repeat itself.

The sample tables I am attempting to work with are Parts and
Revisions. Where each revision has_many parts and each part
belongs_to revision.

Thanks for any Help!!!

Lewis


#2

ok, so if parts belongs_to Revision, it must have a revision_id
which you must have created in the migration.

Assuming you have a form that sends the Parts data (in params[:parts]
and
you know to which revision it should be added, then

@revision = Revision.find(revision_id) # however you get revision id,
could eg be params[:revision_id]
@revision.parts.create(params[:parts])

would be all you need.
First line getting the revision, next line adding the part to that
revision.
revision_id is set by Rails