pesttopesticide is maintained by relationship() as the "secondary" table, but
the expectation is that rows in this table will be unique. if you are
appending duplicate entries to "pestList" or "pesticide" you may want to use
collection_class=set to maintain uniqueness in the collection.
On Apr 24, 2013, at 12:51 PM, dan <d...@inlet.geol.sc.edu> wrote:
> I've got a many to many relationship with the association table. The issue I
> am running into is that a given pesticide entry may have a pest or pests
> already in the pest table. I don't want to add the pest since it will be a
> duplicate, however I still want the association of that pest to the pesticide
> done.
>
> I've looked at the Unique Object wiki, however I am not sure that solves my
> issue. Is there a way that SQLAlchemy can handle this, or do I need to
> manually build the entries in the PestToPesticide association table?
>
> Thanks!
>
> Dan
>
> PestToPesticide = Table('pest_to_pesticide', Base.metadata,
> Column('pesticide_id', Integer,
> ForeignKey('pesticide.row_id')),
> Column('pest_id', Integer,
> ForeignKey('pest.row_id'))
> )
> class Pesticide(Base):
> __tablename__ = 'pesticide'
> row_id = Column(Integer,primary_key=True)
>
> name = Column(String(64), unique=True)
>
> pestList =relationship("Pest", secondary=PestToPesticide,
> backref="pesticide")
>
> class Pest(object):
> row_id = Column(Integer,primary_key=True)
>
> name = Column(String(), unique=True)
>
>
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