because the join condition is on two primary key columns, the fact that
they are primary keys is overriding the fact that one of them is a foreign
key and its determining the direction of the relationship improperly.
if you give it a clue as to which side of the join is the "foreignkey"
like this, it works:
Person.mapper = mapper(Person, people,
properties = {
'Sites' : relation(PersonSite.mapper, uselist=True,
primaryjoin=(peoplesites.c.person==people.c.key),
foreignkey=peoplesites.c.person),
},
)
however, the SA function that does this, _find_dependent() inside of
sqlalchemy/mapping/properties.py, should probably be fixed to detect this
condition better, so I added ticket #151 for that.
Dimi Shahbaz wrote:
> Hi,
> My abridged schema:
>
>
> people = Table("people", pg_engine,
> Column('key', String, primary_key=True),
> Column('firstname', String),
> Column('lastname', String),
> )
>
> peoplesites = Table("peoplesites", pg_engine,
> Column('person', String, ForeignKey("people.key"),
> primary_key=True),
> Column('site', String),
> )
>
> PersonSite.mapper = mapper(PersonSite, peoplesites)
>
> Person.mapper = mapper(Person, people,
> properties = {
> 'Sites' : relation(PersonSite.mapper, uselist=True,
> primaryjoin=(peoplesites.c.person==people.c.key)),
> },
> )
>
>
> I think that's enough to show my problem. Anyway, I have a method in
> the Person class called addSite() which creates a PersonSite() and
> does something like: self.Sites.append(newPersonSite). When I go to
> do a commit, however, it seems that the INSERTs come in the wrong
> order: the peoplesites insert is done first. This fails, because the
> 'person' field of the peoplesites table is a foreign key of people.key.
>
> My workaround is to do:
> objectsore.commit(newPerson) #Get the person inserted
> objectsore.commit() #Get everything else inserted
>
> I know SA is smart about these things, so I'm probably doing
> something wrong to cause this. What could be the reason?
>
>
>
>
> --
> Dimi Shahbaz, Software Engineer Specialist
> California PASS Program
> www.cyberhigh.fcoe.k12.ca.us
>
>
>
>
>
>
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