Re: [sqlalchemy] Setting the FK not performed when relationship is declared

2020-12-10 Thread Nikola Radovanovic 
Yes, my bad; it should state: # at this moment, child.parent_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  
> 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.
> > ---
> > You received this message because you are subscribed to the Google 
> Groups "sqlalchemy" group.
> > To unsubscribe from this group and stop receiving emails from it, send 
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> > To view this discussion on the web visit 
> https://groups.google.com/d/msgid/sqlalchemy/4704d9db-2725-416f-9ab4-65077209b8f5n%40googlegroups.com
> .
>

-- 
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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Re: [sqlalchemy] Setting the FK not performed when relationship is declared

2020-12-10 Thread Simon King 
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  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.
> ---
> You received this message because you are subscribed to the Google Groups 
> "sqlalchemy" group.
> To unsubscribe from this group and stop receiving emails from it, send an 
> email to sqlalchemy+unsubscr...@googlegroups.com.
> To view this discussion on the web visit 
> https://groups.google.com/d/msgid/sqlalchemy/4704d9db-2725-416f-9ab4-65077209b8f5n%40googlegroups.com.

-- 
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] Setting the FK not performed when relationship is declared

2020-12-10 Thread Nikola Radovanovic 
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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