Re: [Modeling-users] Re: attaching information to a relation

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

I wrote:
> The problem is that you were probably misled here by the names: since
> you read 'typed_assocs' and 'user', you tend to think that associations
> are resp. to-many and to-one, and since the cardinalities are implicit
> here, that makes it harder to see the problem. In fact,=20
>=20
>        Association('User','TypedAssoc',
>          relations=3D['typed_assocs','user'],
>          delete=3D['cascade','nullify'],
>          keys=3D['id','FK_User_id']
>=20
> is equivalent to (see Association's defaults):
>=20
>        Association('User','TypedAssoc',
>          relations=3D['typed_assocs','user'],
>          multiplicity=3D[ [0,1], [0,None] ],
>          delete=3D['cascade','nullify'],
>          keys=3D['id','FK_User_id']
>=20
>   and this version makes the pb appears clearly, doesn't it? ;)

Now I really wonder if this was a so good idea to allow the multiplicity
to be implicit. If you remember the discussion on this topic, we made it
implicit becauser it allows a more concise declarations of associations.
However, this obviously lead, leads (and will lead) to problems, just
because we human-beings interpret things a lot more than machines do :)

  It may be really better to make the multiplicity explicit in
  associations (so that it is required in each declaration of
  association), and allow it to be either E1 <<---> E2 (the only
  possible case for now) or E1 <--->> E1.=20

What do you think, all?

        Regards,

-- S=E9bastien.