Tested trunk and it works now. Thanks!
On Nov 12, 4:44 pm, Michael Bayer <[EMAIL PROTECTED]> wrote:
> whoops...yeah, that is correct but you'll have to use trunk 5287 until
> rc4 comes out (soon). It was stomping on top of 'inherit_condition'
> within the declarative configuration.
>
> On Nov 12, 2008, at 10:25 AM, tante wrote:
>
>
>
> > Ok, I have it like this now:
> > ---------------------------------
> > class Comment(Object):
> > """Allows commenting of any other entity in the server"""
> > __tablename__= 'comments'
>
> > uuid=Column(String(36),ForeignKey
> > ('objects.uuid'),primary_key=True)
> > __mapper_args__ = {'polymorphic_identity': 'comment',
> > 'inherit_condition':uuid==Object.uuid}
>
> > text=Column(String(),nullable=False)
> > author=Column(String(),nullable=False)
> > date=Column(AutoNowDateTime(),nullable=False)
> > subject_id=Column(String(36),ForeignKey('objects.uuid'))
>
> > def __repr__(self):
> > return u"<Comment('%s','%s','%s')>" % (self.author,str
> > (self.date),self.text[:20])
> > -------------------------
>
> > but I still get:
> > ArgumentError: Can't determine join between 'objects' and 'comments';
> > tables have more than one foreign key constraint relationship between
> > them. Please specify the 'onclause' of this join explicitly.
>
> > On Nov 12, 4:10 pm, Michael Bayer <[EMAIL PROTECTED]> wrote:
> >> On Nov 12, 2008, at 9:42 AM, tante wrote:
>
> >>> I'm working on a system that has a Base class called Object. Many
> >>> other classes inherit from this one class via joined table
> >>> inheritance
> >>> and it's working great. But now there's a problem: The subclass
> >>> "Comment" does reference "Object" twice, once for the inheritance
> >>> and
> >>> once as a ForeignKey to mark which object the comment is about.
>
> >>> Code example:
> >>> ----------------------------
> >>> Base = declarative_base()
> >>> class Object(Base):
> >>> "Base class for all our Entities"
>
> >>> __tablename__= 'objects'
>
> >>> uuid=Column(String(36),primary_key=True)
> >>> discriminator=Column(String(30), nullable=False)
>
> >>> __mapper_args__ = {'polymorphic_on': discriminator,
> >>> 'polymorphic_identity': 'object'}
>
> >>> def __init__(self,*args,**kwargs):
> >>> super(Object,self).__init__(*args,**kwargs)
> >>> if not self.uuid:
> >>> # create a random uuid
> >>> self.uuid=str(uuid4())
>
> >>> def __repr__(self):
> >>> return u"<Object('%s')>" % (self.uuid)
>
> >>> class Comment(Object):
> >>> """Allows commenting of any other entity in the server"""
> >>> __tablename__= 'comments'
> >>> __mapper_args__ = {'polymorphic_identity': 'comment'}
>
> >>> uuid=Column(String(36),ForeignKey
> >>> ('objects.uuid'),primary_key=True)
> >>> text=Column(String(),nullable=False)
> >>> author=Column(String(),nullable=False)
> >>> date=Column(AutoNowDateTime(),nullable=False)
> >>> subject_id=Column(String(36),ForeignKey('objects.uuid'))
>
> >>> def __repr__(self):
> >>> return u"<Comment('%s','%s','%s')>" % (self.author,str
> >>> (self.date),self.text[:20])
>
> >>> ------------------
> >>> This leads to this error:
> >>> #ArgumentError: Can't determine join between 'objects' and
> >>> 'comments';
> >>> #tables have more than one foreign key constraint relationship
> >>> between
> >>> them.
> >>> #Please specify the 'onclause' of this join explicitly.
>
> >>> I tried to add __mapper_args__ to Comment like
> >>> "inherit_condition=Comment.c.uuid==Object.c.uuid"
> >>> but while I can get it to initialize, it won't let me query giving
> >>> me
> >>> this error:
> >>> AttributeError: 'PropertyLoader' object has no attribute 'strategy'
>
> >>> How can I allow more than one reference between those Classes?
>
> >> strings aren't recognized for "inherit_condition", so do the dict lke
> >> __mapper_args__ = {'inherit_condition':uuid==Object.uuid}, and place
> >> __mapper_args__ in Comment after you define the "uuid" coumn.
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