Thanks a lot
This works, I cant remember why I was passing the User object as the
argument
How can I mark a post as the answer here?
On Monday, September 3, 2018 at 1:29:10 PM UTC+4:30, Simon King wrote:
>
> Here's a version which I *think* does what you want. There are a
> couple of things that you might want to note.
>
> First, in your paste, Conversation.user1 and Conversation.user2 are
> integer columns, but you are assigning User objects to those
> properties. That's not the way SQLAlchemy works - you can't assign a
> related object directly to the column. In my version below I've
> renamed the columns to "userid1" and "userid2" and then created
> relationships for "user1" and "user2".
>
> Second, the User.conversations property needs to have "viewonly=True".
> It wouldn't make sense for it to be a writable property, because if
> you appended a new Conversation to it, SQLAlchemy wouldn't know which
> of the userid1 or userid2 columns to update.
>
>
> ####################
>
> import sqlalchemy as sa
> import sqlalchemy.orm as saorm
> from sqlalchemy.ext.declarative import declarative_base
>
> Base = declarative_base()
>
>
> class Conversation(Base):
> __tablename__ = 'conversations'
> id = sa.Column(sa.Integer(), primary_key=True)
> userid1 = sa.Column(
> sa.Integer(),
> sa.ForeignKey('users.id'),
> nullable=False,
> )
> userid2 = sa.Column(
> sa.Integer(),
> sa.ForeignKey('users.id'),
> nullable=False,
> )
>
> user1 = saorm.relationship(
> "User",
> primaryjoin="Conversation.userid1 == User.id",
> )
> user2 = saorm.relationship(
> "User",
> primaryjoin="Conversation.userid2 == User.id",
> )
>
>
> class User(Base):
> __tablename__ = 'users'
> id = sa.Column(sa.Integer(), primary_key=True)
> userName = sa.Column(sa.String(32), unique=True, nullable=False)
>
> conversations = saorm.relationship(
> Conversation,
> primaryjoin=sa.or_(
> id == Conversation.userid1,
> id == Conversation.userid2,
> ),
> viewonly=True,
> )
>
>
> if __name__ == '__main__':
> engine = sa.create_engine("sqlite:///:memory:", echo="debug")
> Session = saorm.sessionmaker(bind=engine)
> Base.metadata.create_all(engine)
>
> session = Session()
> u1 = User(userName="Alireza")
> u2 = User(userName="Amir")
> session.add_all([u1, u2])
> session.commit()
>
> con = Conversation(user1=u1, user2=u2)
> session.add(con)
> session.commit()
>
> print u1.conversations
>
>
> ####################
> On Sun, Sep 2, 2018 at 3:27 PM Alireza Ayin Mehr
> <alireza...@gmail.com <javascript:>> wrote:
> >
> > Well, it seems weird this way, I only have one userId in my parent class
> which is the source class
> >
> >
> > On Sunday, September 2, 2018 at 6:08:33 AM UTC+4:30, Seth P wrote:
> >>
> >> In relationship(), foreign_keys refers to the field in the source
> table, not the destination.
> >
> > --
> > SQLAlchemy -
> > The Python SQL Toolkit and Object Relational Mapper
> >
> > http://www.sqlalchemy.org/
> >
> > To post example code, please provide an MCVE: Minimal, Complete, and
> Verifiable Example. See http://stackoverflow.com/help/mcve for a full
> description.
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--
SQLAlchemy -
The Python SQL Toolkit and Object Relational Mapper
http://www.sqlalchemy.org/
To post example code, please provide an MCVE: Minimal, Complete, and Verifiable
Example. See http://stackoverflow.com/help/mcve for a full description.
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