Thanks! I don't quite follow the statement about "fully mapped
association table" being unusual. The first Many-to-Many example you
linked was the structure I copied when making my own tables here. Have
I deviated from it in some way? Or should the example on the site have
viewonly=True, if being used with InnoDB? Perhaps I just wasn't being
clear in my reproducing them here. Just once again now, with the
additional relevant bits in:
class Base(object):
id = Column(Integer, primary_key=True)
__table_args__ = {'mysql_engine': 'InnoDB'}
Base = declarative_base(cls=Base)
class Event(Base):
....
Avalanche_Event_Association = Table('Avalanche_Event_Association',
Base.metadata,
Column('avalanche_id', Integer, ForeignKey('Avalanche.id')),
Column('event_id', Integer, ForeignKey('Event.id')),
mysql_engine='InnoDB')
class Avalanche(Base):
events = relationship("Event",
secondary=Avalanche_Event_Association)
....
Doing Base.metadata.create_all(engine) yields an error creating the
Avalanche_Event_Association table.
On May 31, 3:28 pm, Michael Bayer <[email protected]> wrote:
> create_all() only can determine the order of tables if you use ForeignKey and
> ForeignKeyConstraint objects correctly on the source Table objects and/or
> declarative classes.
>
> Seehttp://docs.sqlalchemy.org/en/rel_0_7/orm/relationships.html#many-to-...andhttp://docs.sqlalchemy.org/en/rel_0_7/orm/relationships.html#associat...for
> examples of these configurations. Note that mixing a fully mapped
> association object and "secondary" is a bit unusual and you'll want
> viewonly=True if you're doing that.
>
> On May 31, 2012, at 2:32 PM, Jeff wrote:
>
>
>
>
>
>
>
> > Perhaps it's relevant (though I suspect not) that the class Avalanche
> > actually contains:
>
> > class Avalanche(Base):
> > ....
> > events = relationship("Event",
> > secondary=Avalanche_Event_Association)
>
> > This is what prevents us from writing the classes in the following
> > order in the database definition .py file:
>
> > class Event(Base):
> > .....
>
> > class Avalanche(Base):
> > ....
>
> > Avalanche_Event_Association = Table('Avalanche_Event_Association',
> > ....
>
> > Because Avalanche needs to reference Avalanche_Event_Association. I
> > hope, however, that the the create_all function is able to
> > appropriately create the tables anyway, regardless of their order in
> > the database definition .py file.
>
> > Thanks!
>
> > On May 31, 2:21 pm, Jeff <[email protected]> wrote:
> >> The tables don't exist yet. The Base.metadata.create_all(engine) is to
> >> create them.
>
> >> Thanks!
>
> >> On May 30, 11:52 pm, Michael Bayer <[email protected]> wrote:
>
> >>> This might be because the tables you're trying to reference are
> >>> themselves not InnoDB. Try running DESCRIBE on the referenced tables at
> >>> the MySQL console to help confirm this, as well as the same CREATE TABLE
> >>> statement below.
>
> >>> On May 30, 2012, at 11:31 PM, Jeff wrote:
>
> >>>> Having difficulty creating a database that includes the following
> >>>> plumbing:
>
> >>>> class Base(object):
> >>>> id = Column(Integer, primary_key=True)
> >>>> __table_args__ = {'mysql_engine': 'InnoDB'}
>
> >>>> Base = declarative_base(cls=Base)
>
> >>>> class Event(Base):
> >>>> ....
>
> >>>> Avalanche_Event_Association = Table('Avalanche_Event_Association',
> >>>> Base.metadata,
> >>>> Column('avalanche_id', Integer, ForeignKey('Avalanche.id')),
> >>>> Column('event_id', Integer, ForeignKey('Event.id')),
> >>>> mysql_engine='InnoDB')
>
> >>>> class Avalanche(Base):
> >>>> ....
>
> >>>> Doing Base.metadata.create_all(engine) yields:
>
> >>>> OperationalError: (OperationalError) (1005, "Can't create table
> >>>> 'alstottj.Avalanche_Event_Association' (errno: 150)") '\nCREATE TABLE
> >>>> `Avalanche_Event_Association` (\n\tavalanche_id INTEGER, \n\tevent_id
> >>>> INTEGER, \n\tFOREIGN KEY(avalanche_id) REFERENCES `Avalanche` (id), \n
> >>>> \tFOREIGN KEY(event_id) REFERENCES `Event` (id)\n)ENGINE=InnoDB\n
> >>>> \n' ()
>
> >>>> Commenting out the line "mysql_engine='InnoDB'" removes the error and
> >>>> the tables are all created, but the association table is now MyISAM.
>
> >>>> I have some feelings on what could be causing the error, but they all
> >>>> seem improbable. Thoughts?
>
> >>>> --
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>
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