all modules which include mapped classes must be imported before you attempt to
initialize the mappings. If class A references "B", but "class B" doesn't
exist, you get errors like that, so importing the modules that contain both
class A and B solves the issue.
On Oct 25, 2010, at 2:55 PM, Alvaro Reinoso wrote:
> Hello,
>
> I get errors when I try to create tables one to one relation. Screen
> contains crm and crm contains more classes. The relation is one to one
> between crm, so I want to use the screen id as primary key in crm. And
> the relation is one to one between crm and some classes, I just added
> one class as example, so children of crm must contain a screen id as a
> primary key. When I try to make the last relation, it's when it
> breaks. I tried to use both, crm id and screen id.
>
> I didn't work. I get errors such as, "UnmappedClassError" when I try
> to use crm id in ContactInformation, and "Could not determine join
> condition between parent/child tables on relationship
> CRM.contactInformation. Specify a 'primaryjoin' expression. If this is
> a many-to-many relationship, 'secondaryjoin' is needed as well" when I
> try to use screen id in ContactInformation.
>
> These are my classes:
>
> class Screen(rdb.Model):
>"""Set up screens table in the database"""
>rdb.metadata(metadata)
>rdb.tablename("screens")
>
>id = Column("id", Integer, primary_key=True)
>title = Column("title", String(100))
>
>
>crm = relationship("CRM", uselist=False, backref="screens")
>
> class CRM(rdb.Model):
>"""Set up crm table in the database"""
>rdb.metadata(metadata)
>rdb.tablename("crms")
>
>id = Column("id", Integer, ForeignKey("screens.id"),
> primary_key=True)
>
>contactInformation = relationship("crm_contact_informations",
> uselist=False, backref="crms")
>
>
> class CRMContactInformation(rdb.Model):
>"""Set up crm contact information table in the database"""
>rdb.metadata(metadata)
>rdb.tablename("crm_contact_informations")
>
>id = Column("id", Integer, ForeignKey("screens.id"),
> primary_key=True)
>owner = Column("owner", String(50))
> ...
>
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