Yes, my bad; it should state: # at this moment, child.parent_id
<http://child.id/> is None. What is strange, when added single_parent=True
to the relationship - it then worked as I would expected. I guess its some
of my misunderstanding of how relationship works. In case needed, I will
set working sample, this one was just extracted from more complicated code.
Thanks!
On Thursday, December 10, 2020 at 11:00:40 AM UTC+1 Simon King wrote:
> I can't see anything obviously wrong with what you've written (you
> said "child.id is None", but I assume you meant child.parent_id). Can
> you provide a runnable example?
>
> Simon
>
> On Thu, Dec 10, 2020 at 8:27 AM Nikola Radovanovic <niko...@gmail.com>
> wrote:
> >
> > Hi,
> > I have a FK in child pointing to parent table. Also, there is a
> relationship towards parent from children. I would like to create children
> and set FK to parent explicitly, without previously loading the parent
> object. After commit, FK of parent in child table is None. In case I remove
> relationship from child to parent, FK is set properly.
> >
> > Here is the simplified code:
> >
> > class Child(Base):
> > __tablename__ = 'children'
> > id = Column(Integer, primary_key=True)
> > parent_id = Column(Integer, ForeignKey('parent.id',
> ondelete="CASCADE"), nullable=True)
> >
> > parent = relationship("Parent", uselist=False) ## <-- when removing
> this, it works
> >
> > class Parent(Base):
> > __tablename__ = 'parent'
> > id = Column(Integer, primary_key=True)
> >
> > child = Child(parent_id=3)
> > session.add(child)
> > session.commit()
> >
> > # at this moment, child.id is None and not 3., although parent with id
> ==3 exists in the DB. DB is Postgres 12.
> >
> > I have tried different loading techniques, but nothing worked.
> >
> > Can someone please point me into the right direction?
> >
> > Thank you in advance.
> >
> > Kindest regards
> >
> > --
> > 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/
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