On Feb 24, 2010, at 6:14 AM, flya flya wrote:
> Yes, this is what I wonder, but my code use orm, declarative_base(), not
> mapper, I write these code follow the document's example, it can't work too,
> what's wrong with my code?
>
> Base = declarative_base()
> class Page(Base):
> __tablename__ = 'pages'
> id = Column(Integer, primary_key=True)
> parent_id = Column('parent_id', Integer, ForeignKey('pages.id'))
>
> children = relation('Page')
> parent = relation('Page', remote_side=['pages.c.id'])
no quotes unless the [] are in there as well. See this FAQ entry:
http://www.sqlalchemy.org/trac/wiki/FAQ#ImusingDeclarativeandsettingprimaryjoinsecondaryjoinusinganand_oror_andIamgettinganerrormessageaboutforeignkeys.
>
> when insert a data, raise the error information:
> raise sa_exc.ArgumentError("Relation %s could not determine any local/remote
> column pairs from remote side argument %r" % (self, self.remote_side))
> sqlalchemy.exc.ArgumentError: Relation Page.parent could not determine any
> local/remote column pairs from remote side argument
> set([<sqlalchemy.sql.expression.ColumnClause at 0xa17690c; pages.c.id>])
>
>
> On Wed, Feb 24, 2010 at 3:39 PM, Oliver Beattie <[email protected]> wrote:
> > You probably want to take a look at
> > http://www.sqlalchemy.org/docs/05/mappers.html#adjacency-list-relationships
> >
> > On Feb 23, 5:42 pm, flya flya <[email protected]> wrote:
> >> here is code:
> >>
> >> Base = declarative_base()
> >> class Page(Base):
> >> __tablename__ = 'pages'
> >> id = Column(Integer, primary_key=True)
> >> parent_id = Column('parent_id', Integer, ForeignKey('pages.id'))
> >>
> >> children = relation('Page', backref='parent')
> >>
> >> I get error information：
> >> sqlalchemy.exc.ArgumentError: Page.children and back-reference
> >> Page.parent are both of the same direction <symbol 'ONETOMANY>. Did
> >> you mean to set remote_side on the many-to-one side ?
> >>
> >> when change the code
> >> children = relation('Page', backref='parent')
> >> to
> >> childen = relation('Page')
> >> It can work , but I can only get 'children' no 'parent' from a Page
> >> instant.
> >
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>
>
>
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