Got it. Many thanks!
On Tue, Feb 22, 2011 at 7:02 PM, Michael Bayer <mike...@zzzcomputing.com>wrote:
>
> one side scalar, one side collection. the collection side you use
> .append(). You decide which end is the non-collection by setting
> remote_side, in your code below its "invitee".
>
>
> On Feb 22, 2011, at 9:59 PM, Ryan McKillen wrote:
>
> I added that in because without it I get:
> TypeError: Incompatible collection type: User is not list-like
>
>
> On Tue, Feb 22, 2011 at 6:47 PM, Michael Bayer
> <mike...@zzzcomputing.com>wrote:
>
>>
>> On Feb 22, 2011, at 9:03 PM, Ryan McKillen wrote:
>>
>> Mike, thanks a lot. Big help. I'm almost there.
>>
>> This seems to do the trick:
>>
>> usersid = Column(Integer, primary_key=True, key='id')
>> inviter_id = Column(Integer, ForeignKey('users.id'))
>>
>> inviter = relationship('User',
>> uselist = False,
>> backref = backref('invitee', remote_side=usersid, uselist=True),
>> )
>>
>> When there are two users, one being the inviter (parent) and the other
>> being the invitee (child), it works like a charm:
>>
>> self.assertEqual(invitee1.inviter.id, inviter.id)
>> self.assertEqual(inviter.invitee[0].id, invitee1.id)
>>
>> But add a third user, one being the inviter and two being the invitees,
>> invitee1.inviter is None.
>>
>>
>> probably because of that uselist=False, which makes it into a one-to-one.
>> Adjacency list is a standard single foreign key relationship -
>> one-to-many on one side, many-to-one on the other.
>>
>> There's an illustration of exactly how the data resides in the table:
>>
>>
>> http://www.sqlalchemy.org/docs/orm/relationships.html#adjacency-list-relationships
>>
>>
>>
>>
>> Any ideas for me?
>>
>>
>> On Tue, Feb 22, 2011 at 7:54 AM, Michael Bayer
>> <mike...@zzzcomputing.com>wrote:
>>
>>>
>>> On Feb 20, 2011, at 10:12 PM, Ryan wrote:
>>>
>>> I'm attempting a self-referential mapping on a Client object that
>>> includes these two columns:
>>>
>>> id = Column(Integer, primary_key=True)
>>> inviter_id = Column(Integer, ForeignKey('users.id'), nullable=True)
>>>
>>>
>>> Started here with no luck:
>>>
>>> inviter = relationship('Client', primaryjoin='Client.id ==
>>> Client.inviter_id', uselist=False)
>>>
>>>
>>> Then read about self-referential mapping in the docs and tried with no
>>> luck:
>>>
>>> inviter = relationship('Client', remote_side='Client.id', uselist=False)
>>>
>>>
>>> And this with an error:
>>>
>>> relationship('Client', remote_side=[Client.id], uselist=False)
>>>
>>>
>>> Would be a great help to see how this is done in a declarative style.
>>> Thanks!
>>>
>>>
>>>
>>> the last example in the section
>>> http://www.sqlalchemy.org/docs/orm/relationships.html#adjacency-list-relationshipsillustrates
>>> a declarative self-referential relationship. Note that the "id"
>>> Column object can be referenced directly when you're inside the class
>>> declaration itself.
>>>
>>>
>>>
>>>
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>>
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