On page 23 of the 0.9.7 (Section 2.1.10, Building A Relationship) I see
the example:
class Address(Base):
__tablename__ = 'addresses'
id = Column(Integer, primary_key=True)
email_address = Column(String, nullable=False)
user_id = Column(Integer, ForeignKey('users.id'))
user = relationship("User", backref=backref('addresses', order_by=id))
The last line is in the child table (with the foreign key) and the
backref() statement has the child table name and an order_by option) Why
is backref written twice, and why is the parent table (user/User) mentioned
twice? Or, is 'user' a column in the addresses table?
On page 89 (Section 2.3.3, Linking Relationships With Backref) I see a
different example:
class User(Base):
__tablename__ = 'user'
id = Column(Integer, primary_key=True)
name = Column(String)
addresses = relationship("Address", backref="user")
class Address(Base):
__tablename__ = 'address'
id = Column(Integer, primary_key=True)
email = Column(String)
user_id = Column(Integer, ForeignKey('user.id'))
Here, the relationship() statement is in the parent table and it specifies
the child class "Address" with backref mentioned once to the parent table
"user".
These two examples appear different to me. If no one can clear up my
confusion I'll wait for Mike to return from vacation to be straightened out
on how to define referencial integrity.
Thanks,
Rich
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