Am Donnerstag, 13. Februar 2014 18:01:27 UTC+1 schrieb Michael Bayer:
>
>
> On Feb 13, 2014, at 11:46 AM, Guido Winkelmann <
> gu...@ambient-entertainment.de <javascript:>> wrote:
>
>
>
> Am Donnerstag, 13. Februar 2014 15:46:31 UTC+1 schrieb Michael Bayer:
>>
>>
>> On Feb 13, 2014, at 6:23 AM, Guido Winkelmann <
>> gu...@ambient-entertainment.de> wrote:
>>
>> > Hi,
>> >
>> > Reading through the docs, I could not find out how to tell the
>> cardinality of an object of type
>> sqlalchemy.orm.properties.RelationshipProperty, i.e. whether it is
>> one-to-many, many-to-one or many-to-many. Mostly, I just need to know
>> whether a relationship refers to just one object or a collection of
>> objects.
>> >
>> > Can someone help me with that?
>>
>> So given a class:
>>
>> MyClass
>>
>> and a relationship at the class level:
>>
>> MyClass.some_relationship
>>
>> you get at the RelationshipProperty like this:
>>
>> MyClass.some_relationship.property
>>
>
> That doesn't work for me.
>
> For some reason, the relationship has the type
> sqlalchemy.orm.dynamic.AppenderBaseQuery, which has no attribute "property".
>
> Maybe that's because I'm using flask-sqlalchemy instead of just sqlalchemy
> directly?
>
>
> “MyClass” is a class, not an object:
>
> from sqlalchemy import *
> from sqlalchemy.orm import *
> from sqlalchemy.ext.declarative import declarative_base
>
> Base = declarative_base()
>
> class A(Base):
> __tablename__ = 'a'
>
> id = Column(Integer, primary_key=True)
> bs = relationship("B", lazy="dynamic")
>
>
> class B(Base):
> __tablename__ = 'b'
>
> id = Column(Integer, primary_key=True)
> a_id = Column(Integer, ForeignKey('a.id'))
>
> configure_mappers()
>
> print A.bs.property
>
Thanks, that helped!
Guido W.
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