Well the other way doesn't quite work as if I mark none of the columns as
foreign in the primary join, sqla then assumes / guesses all of them are.
Let me test with passive.
On Wed, Oct 10, 2018, 13:30 Mike Bayer <mike...@zzzcomputing.com> wrote:
> On Wed, Oct 10, 2018 at 1:27 PM Alex Rothberg <agrothb...@gmail.com>
> wrote:
> >
> > And I'll reiterate, not worth doing it all from the original single
> relationship (ie not needing to either add more relationships, have
> warnings or use the more obscure feature you outlined)? Seems like that
> would be cleaner in code.
>
> you mean take the viewonly=True off the existing relationship? sure
> you can do that. but if you mutate the elements in that collection,
> you can incur a change that is conflicting with the other objects.
> that's why I suggested making the non-viewonly a private member, but
> either way works.
>
>
> >
> > On Wed, Oct 10, 2018, 13:17 Mike Bayer <mike...@zzzcomputing.com> wrote:
> >>
> >> the raise load issue is because without passive_deletes, it has to
> >> load the collection to make sure those objects are all updated.
> >> passive_deletes fixes, now you just have a warning. or use the unit
> >> of work recipe which is more direct.
> >> On Wed, Oct 10, 2018 at 1:15 PM Alex Rothberg <agrothb...@gmail.com>
> wrote:
> >> >
> >> > Not just for warning. Also this raise load issue. yes, i see that I
> can't mark none. If I could though, that would be awesome since I think it
> would solve this problem? I can test by setting one foreign and seeing if
> that works.
> >> >
> >> > On Wednesday, October 10, 2018 at 1:13:32 PM UTC-4, Mike Bayer wrote:
> >> >>
> >> >> On Wed, Oct 10, 2018 at 12:56 PM Alex Rothberg <agrot...@gmail.com>
> wrote:
> >> >> >
> >> >> > let me get that. in the meantime, what are your thoughts on just
> removing the view only from the original relationship and then using an
> explicit primary join where none of the columns are marked foreign?
> Theoretically that should solve this problem, no?
> >> >>
> >> >> is this just for the warning? I don't think the relationship() can
> >> >> be set up with no columns marked as foreign, it takes that as a cue
> >> >> that it should figure out the "foreign" columns on its own.
> >> >>
> >> >> There's another way to make sure Employee is always dependent on
> >> >> FundTitle but it's a little bit off-label. Add the dependency you
> >> >> want directly into the unit of work:
> >> >>
> >> >> from sqlalchemy.orm import unitofwork
> >> >> from sqlalchemy import event
> >> >>
> >> >>
> >> >> @event.listens_for(Session, "before_flush")
> >> >> def _add_dep(session, context, objects):
> >> >> context.dependencies.update([
> >> >> (
> >> >> unitofwork.SaveUpdateAll(context, inspect(FundTitle)),
> >> >> unitofwork.SaveUpdateAll(context, inspect(Employee))
> >> >> )
> >> >> ])
> >> >>
> >> >>
> >> >>
> >> >>
> >> >>
> >> >> >
> >> >> > On Wednesday, October 10, 2018 at 12:41:25 PM UTC-4, Alex Rothberg
> wrote:
> >> >> >>
> >> >> >> Is it possible to specific a non viewonly relationship in which I
> have a primary join specified in which none of the fk's are marked
> "foreign"? ie where I can mark the relationship dependancy but it wont set
> any columns? It looks like there may be some logic in sqla that assume all
> columns are fk if none are specified as foreign?
> >> >> >>
> >> >> >> On Wednesday, October 10, 2018 at 11:56:49 AM UTC-4, Alex
> Rothberg wrote:
> >> >> >>>
> >> >> >>> So one minor issue and one big issue with that solution:
> >> >> >>> 1. minor issue, I now get these: SAWarning: relationship 'XXXX'
> will copy columnYYYY to column ZZZZ, which conflicts with relationship(s):
> '....
> >> >> >>> 2. major issue, I use raiseload("*") and now I start seeing:
> sqlalchemy.exc.InvalidRequestError: 'Employee._ft_for_dependency' is not
> available due to lazy='raise'
> >> >> >>>
> >> >> >>> On Wednesday, October 10, 2018 at 9:57:55 AM UTC-4, Mike Bayer
> wrote:
> >> >> >>>>
> >> >> >>>> On Tue, Oct 9, 2018 at 6:45 PM Alex Rothberg <
> agrot...@gmail.com> wrote:
> >> >> >>>> >
> >> >> >>>> > Okay with some small tweaks to your original code, I am able
> to show the issue I am having. comment out flush to see issue:
> >> >> >>>>
> >> >> >>>> so what you're doing here is making Employee dependent on
> FundTitle,
> >> >> >>>> which makes this a little out of the ordinary but this is
> fine. You
> >> >> >>>> need to give the ORM a clue that this dependency exists, since
> it
> >> >> >>>> never looks at foreign key constraints unless you tell it to.
> >> >> >>>> Adding a relationship to FundTitle that doesn't have
> viewonly=True is
> >> >> >>>> an easy way to do this, there's no need to ever make use of the
> >> >> >>>> relationship otherwise:
> >> >> >>>>
> >> >> >>>> class Employee(Base):
> >> >> >>>> __tablename__ = 'employee'
> >> >> >>>>
> >> >> >>>> # ...
> >> >> >>>> fund_title = relationship(FundTitle, viewonly=True)
> >> >> >>>>
> >> >> >>>> _ft_for_dependency = relationship(FundTitle)
> >> >> >>>>
> >> >> >>>> __table_args__ = (
> >> >> >>>> ForeignKeyConstraint(
> >> >> >>>> (title_id, department_id, fund_id),
> >> >> >>>> (FundTitle.title_id, FundTitle.department_id,
> FundTitle.fund_id)
> >> >> >>>> ),
> >> >> >>>> )
> >> >> >>>>
> >> >> >>>> then you can take the flush() out and there's no issue, as long
> as
> >> >> >>>> you're always making sure that FundTitle object is present
> either in
> >> >> >>>> the current Session or the row in the database exists.
> >> >> >>>>
> >> >> >>>>
> >> >> >>>> >
> >> >> >>>> > from sqlalchemy import *
> >> >> >>>> > from sqlalchemy.orm import *
> >> >> >>>> > from sqlalchemy.ext.declarative import declarative_base
> >> >> >>>> >
> >> >> >>>> > Base = declarative_base()
> >> >> >>>> >
> >> >> >>>> >
> >> >> >>>> > class Title(Base):
> >> >> >>>> > __tablename__ = 'title'
> >> >> >>>> > id = Column(Integer, primary_key=True)
> >> >> >>>> > department_id = Column(ForeignKey('department.id'),
> nullable=False)
> >> >> >>>> >
> >> >> >>>> > department = relationship(lambda: Department)
> >> >> >>>> >
> >> >> >>>> >
> >> >> >>>> > class Department(Base):
> >> >> >>>> > __tablename__ = 'department'
> >> >> >>>> > id = Column(Integer, primary_key=True)
> >> >> >>>> >
> >> >> >>>> >
> >> >> >>>> > class Fund(Base):
> >> >> >>>> > __tablename__ = 'fund'
> >> >> >>>> > id = Column(Integer, primary_key=True)
> >> >> >>>> > title_id = Column(ForeignKey('title.id'), nullable=False)
> >> >> >>>> > department_id = Column(ForeignKey('department.id'),
> nullable=False)
> >> >> >>>> > department = relationship("Department")
> >> >> >>>> > title = relationship("Title")
> >> >> >>>> >
> >> >> >>>> >
> >> >> >>>> > class FundTitle(Base):
> >> >> >>>> > __tablename__ = 'fund_title'
> >> >> >>>> > id = Column(Integer, primary_key=True)
> >> >> >>>> > title_id = Column(ForeignKey('title.id'), nullable=False)
> >> >> >>>> > department_id = Column(ForeignKey('department.id'),
> nullable=False)
> >> >> >>>> > fund_id = Column(ForeignKey('fund.id'), nullable=False)
> >> >> >>>> > department = relationship("Department")
> >> >> >>>> > title = relationship("Title")
> >> >> >>>> > fund = relationship("Fund")
> >> >> >>>> >
> >> >> >>>> > __table_args__ = (
> >> >> >>>> > UniqueConstraint(
> >> >> >>>> > title_id, department_id, fund_id
> >> >> >>>> > ),
> >> >> >>>> > )
> >> >> >>>> >
> >> >> >>>> >
> >> >> >>>> > class Employee(Base):
> >> >> >>>> > __tablename__ = 'employee'
> >> >> >>>> > id = Column(Integer, primary_key=True)
> >> >> >>>> > title_id = Column(ForeignKey('title.id'), nullable=False)
> >> >> >>>> > department_id = Column(ForeignKey('department.id'),
> nullable=False)
> >> >> >>>> > fund_id = Column(ForeignKey('fund.id'), nullable=False)
> >> >> >>>> >
> >> >> >>>> > department = relationship(lambda: Department)
> >> >> >>>> > title = relationship("Title")
> >> >> >>>> > fund = relationship("Fund")
> >> >> >>>> >
> >> >> >>>> > fund_title = relationship(FundTitle, viewonly=True)
> >> >> >>>> >
> >> >> >>>> >
> >> >> >>>> > __table_args__ = (
> >> >> >>>> > ForeignKeyConstraint(
> >> >> >>>> > (title_id, department_id, fund_id),
> (FundTitle.title_id, FundTitle.department_id, FundTitle.fund_id)
> >> >> >>>> > ),
> >> >> >>>> > )
> >> >> >>>> >
> >> >> >>>> >
> >> >> >>>> > e = create_engine("postgresql://localhost/test_issue",
> echo=False)
> >> >> >>>> >
> >> >> >>>> > # Base.metadata.drop_all(e)
> >> >> >>>> > Base.metadata.create_all(e)
> >> >> >>>> >
> >> >> >>>> > s = Session(e)
> >> >> >>>> > # s.rollback()
> >> >> >>>> >
> >> >> >>>> > while True:
> >> >> >>>> > d1 = Department()
> >> >> >>>> > t1 = Title(department=d1)
> >> >> >>>> > f1 = Fund(department=d1, title=t1)
> >> >> >>>> > ft1 = FundTitle(title=t1, department=d1, fund=f1)
> >> >> >>>> >
> >> >> >>>> > s.add_all([d1, t1, f1, ft1])
> >> >> >>>> >
> >> >> >>>> > s.flush()
> >> >> >>>> >
> >> >> >>>> > e1 = Employee(title=t1, department=d1, fund=f1)
> >> >> >>>> >
> >> >> >>>> > s.add_all([e1,])
> >> >> >>>> > s.commit()
> >> >> >>>> >
> >> >> >>>> > On Tuesday, October 9, 2018 at 12:20:30 PM UTC-4, Mike Bayer
> wrote:
> >> >> >>>> >>
> >> >> >>>> >> On Tue, Oct 9, 2018 at 10:44 AM Alex Rothberg <
> agrot...@gmail.com> wrote:
> >> >> >>>> >> >
> >> >> >>>> >> > In looking at what you wrote doesn't this cause an fk
> violation (it does for me):
> >> >> >>>> >> > 2018-10-08 10:18:38,760 INFO sqlalchemy.engine.base.Engine
> INSERT INTO employee (title_id, department_id, fund_id) VALUES
> (%(title_id)s, %(department_id)s, %(fund_id)s) RETURNING employee.id
> >> >> >>>> >> > 2018-10-08 10:18:38,763 INFO sqlalchemy.engine.base.Engine
> INSERT INTO fund_title (title_id, department_id, fund_id) VALUES
> (%(title_id)s, %(department_id)s, %(fund_id)s) RETURNING fund_title.id
> >> >> >>>> >> >
> >> >> >>>> >> > in that a a (non deferred) fk is violated between employee
> and fund_title ?
> >> >> >>>> >>
> >> >> >>>> >> see we need to see how youve laid out your
> ForeignKeyConstraints, if
> >> >> >>>> >> they are composite and overlapping, there are additional
> options that
> >> >> >>>> >> may be needed (specifically the post_update flag). you'll
> note I laid
> >> >> >>>> >> out all FKs as single column.
> >> >> >>>> >>
> >> >> >>>> >> >
> >> >> >>>> >> > On Mon, Oct 8, 2018 at 10:20 AM Mike Bayer <
> mik...@zzzcomputing.com> wrote:
> >> >> >>>> >> >>
> >> >> >>>> >> >> On Sun, Oct 7, 2018 at 7:11 PM Alex Rothberg <
> agrot...@gmail.com> wrote:
> >> >> >>>> >> >> >
> >> >> >>>> >> >> > Okay so I investigated / thought about this further.
> The issue is that while I do have a relationship between the various
> models, some of the relationships are viewonly since I have overlapping fks.
> >> >> >>>> >> >> >
> >> >> >>>> >> >> > For example I have a model Employee, which has fks:
> department_id, title_id, and fund_id. The related models are Department (fk
> department_id), Title (fk department_id and title_id) , Fund (fk fund_id)
> and FundTitle (fk department_id, title_id and fund_id). I have set
> FundTitle to viewonly. When updating / creating an Employee, I do create
> and add a new FundTitle to the session, however I don't assign it to the
> employee as the relationship is viewonly. If I don't flush before making
> the assignment, the final flush / commit attempts to update / create the
> employee before creating the FundTitle.
> >> >> >>>> >> >>
> >> >> >>>> >> >> let's work with source code that is runnable (e.g.
> MCVE). Below is
> >> >> >>>> >> >> the model that it seems you are describing, and then
> there's a
> >> >> >>>> >> >> demonstration of assembly of all those components using
> relationships,
> >> >> >>>> >> >> a single flush and it all goes in in the correct order,
> all FKs are
> >> >> >>>> >> >> nullable=False.
> >> >> >>>> >> >>
> >> >> >>>> >> >> from sqlalchemy import *
> >> >> >>>> >> >> from sqlalchemy.orm import *
> >> >> >>>> >> >> from sqlalchemy.ext.declarative import declarative_base
> >> >> >>>> >> >>
> >> >> >>>> >> >> Base = declarative_base()
> >> >> >>>> >> >>
> >> >> >>>> >> >>
> >> >> >>>> >> >> class Employee(Base):
> >> >> >>>> >> >> __tablename__ = 'employee'
> >> >> >>>> >> >> id = Column(Integer, primary_key=True)
> >> >> >>>> >> >> title_id = Column(ForeignKey('title.id'),
> nullable=False)
> >> >> >>>> >> >> department_id = Column(ForeignKey('department.id'),
> nullable=False)
> >> >> >>>> >> >> fund_id = Column(ForeignKey('fund.id'),
> nullable=False)
> >> >> >>>> >> >> department = relationship("Department")
> >> >> >>>> >> >> title = relationship("Title")
> >> >> >>>> >> >> fund = relationship("Fund")
> >> >> >>>> >> >>
> >> >> >>>> >> >>
> >> >> >>>> >> >> class Title(Base):
> >> >> >>>> >> >> __tablename__ = 'title'
> >> >> >>>> >> >> id = Column(Integer, primary_key=True)
> >> >> >>>> >> >> department_id = Column(ForeignKey('department.id'),
> nullable=False)
> >> >> >>>> >> >> department = relationship("Department")
> >> >> >>>> >> >>
> >> >> >>>> >> >>
> >> >> >>>> >> >> class Department(Base):
> >> >> >>>> >> >> __tablename__ = 'department'
> >> >> >>>> >> >> id = Column(Integer, primary_key=True)
> >> >> >>>> >> >>
> >> >> >>>> >> >>
> >> >> >>>> >> >> class Fund(Base):
> >> >> >>>> >> >> __tablename__ = 'fund'
> >> >> >>>> >> >> id = Column(Integer, primary_key=True)
> >> >> >>>> >> >> title_id = Column(ForeignKey('title.id'),
> nullable=False)
> >> >> >>>> >> >> department_id = Column(ForeignKey('department.id'),
> nullable=False)
> >> >> >>>> >> >> department = relationship("Department")
> >> >> >>>> >> >> title = relationship("Title")
> >> >> >>>> >> >>
> >> >> >>>> >> >>
> >> >> >>>> >> >> class FundTitle(Base):
> >> >> >>>> >> >> __tablename__ = 'fund_title'
> >> >> >>>> >> >> id = Column(Integer, primary_key=True)
> >> >> >>>> >> >> title_id = Column(ForeignKey('title.id'),
> nullable=False)
> >> >> >>>> >> >> department_id = Column(ForeignKey('department.id'),
> nullable=False)
> >> >> >>>> >> >> fund_id = Column(ForeignKey('fund.id'),
> nullable=False)
> >> >> >>>> >> >> department = relationship("Department")
> >> >> >>>> >> >> title = relationship("Title")
> >> >> >>>> >> >> fund = relationship("Fund")
> >> >> >>>> >> >>
> >> >> >>>> >> >> e = create_engine("postgresql://scott:tiger@localhost/test",
> echo=True)
> >> >> >>>> >> >> Base.metadata.create_all(e)
> >> >> >>>> >> >>
> >> >> >>>> >> >> s = Session(e)
> >> >> >>>> >> >>
> >> >> >>>> >> >> d1 = Department()
> >> >> >>>> >> >> t1 = Title(department=d1)
> >> >> >>>> >> >> f1 = Fund(department=d1, title=t1)
> >> >> >>>> >> >> ft1 = FundTitle(title=t1, department=d1, fund=f1)
> >> >> >>>> >> >> e1 = Employee(title=t1, department=d1, fund=f1)
> >> >> >>>> >> >>
> >> >> >>>> >> >> s.add_all([d1, t1, f1, ft1, e1])
> >> >> >>>> >> >> s.commit()
> >> >> >>>> >> >>
> >> >> >>>> >> >>
> >> >> >>>> >> >> the INSERTs can be ordered naturally here and the unit of
> work will do
> >> >> >>>> >> >> that for you if you use relationship:
> >> >> >>>> >> >>
> >> >> >>>> >> >> BEGIN (implicit)
> >> >> >>>> >> >> 2018-10-08 10:18:38,750 INFO
> sqlalchemy.engine.base.Engine INSERT INTO
> >> >> >>>> >> >> department DEFAULT VALUES RETURNING department.id
> >> >> >>>> >> >> 2018-10-08 10:18:38,750 INFO
> sqlalchemy.engine.base.Engine {}
> >> >> >>>> >> >> 2018-10-08 10:18:38,753 INFO
> sqlalchemy.engine.base.Engine INSERT INTO
> >> >> >>>> >> >> title (department_id) VALUES (%(department_id)s)
> RETURNING title.id
> >> >> >>>> >> >> 2018-10-08 10:18:38,753 INFO
> sqlalchemy.engine.base.Engine {'department_id': 1}
> >> >> >>>> >> >> 2018-10-08 10:18:38,757 INFO
> sqlalchemy.engine.base.Engine INSERT INTO
> >> >> >>>> >> >> fund (title_id, department_id) VALUES (%(title_id)s,
> >> >> >>>> >> >> %(department_id)s) RETURNING fund.id
> >> >> >>>> >> >> 2018-10-08 10:18:38,757 INFO sqlalchemy.engine.base.Engine
> >> >> >>>> >> >> {'title_id': 1, 'department_id': 1}
> >> >> >>>> >> >> 2018-10-08 10:18:38,760 INFO
> sqlalchemy.engine.base.Engine INSERT INTO
> >> >> >>>> >> >> employee (title_id, department_id, fund_id) VALUES
> (%(title_id)s,
> >> >> >>>> >> >> %(department_id)s, %(fund_id)s) RETURNING employee.id
> >> >> >>>> >> >> 2018-10-08 10:18:38,761 INFO sqlalchemy.engine.base.Engine
> >> >> >>>> >> >> {'title_id': 1, 'department_id': 1, 'fund_id': 1}
> >> >> >>>> >> >> 2018-10-08 10:18:38,763 INFO
> sqlalchemy.engine.base.Engine INSERT INTO
> >> >> >>>> >> >> fund_title (title_id, department_id, fund_id) VALUES
> (%(title_id)s,
> >> >> >>>> >> >> %(department_id)s, %(fund_id)s) RETURNING fund_title.id
> >> >> >>>> >> >> 2018-10-08 10:18:38,764 INFO sqlalchemy.engine.base.Engine
> >> >> >>>> >> >> {'title_id': 1, 'department_id': 1, 'fund_id': 1}
> >> >> >>>> >> >> 2018-10-08 10:18:38,766 INFO
> sqlalchemy.engine.base.Engine COMMIT
> >> >> >>>> >> >>
> >> >> >>>> >> >>
> >> >> >>>> >> >>
> >> >> >>>> >> >>
> >> >> >>>> >> >>
> >> >> >>>> >> >> >
> >> >> >>>> >> >> > On Tuesday, September 18, 2018 at 9:02:30 AM UTC-4,
> Mike Bayer wrote:
> >> >> >>>> >> >> >>
> >> >> >>>> >> >> >> if there are no dependencies between two particular
> objects of
> >> >> >>>> >> >> >> different classes, say A and B, then there is no
> deterministic
> >> >> >>>> >> >> >> ordering between them. For objects of the same
> class, they are
> >> >> >>>> >> >> >> inserted in the order in which they were added to the
> Session.
> >> >> >>>> >> >> >>
> >> >> >>>> >> >> >> the correct way to solve this problem in SQLAlchemy is
> to use
> >> >> >>>> >> >> >> relationship() fully. I know you've stated that these
> objects have a
> >> >> >>>> >> >> >> relationship() between them but you have to actually
> use it, that is:
> >> >> >>>> >> >> >>
> >> >> >>>> >> >> >> obj_a = A()
> >> >> >>>> >> >> >> obj_b = B()
> >> >> >>>> >> >> >>
> >> >> >>>> >> >> >> obj_a.some_relationship = obj_b # will definitely
> flush correctly
> >> >> >>>> >> >> >> unless there is a bug
> >> >> >>>> >> >> >>
> >> >> >>>> >> >> >> OTOH if you are only using foreign key attributes, the
> ORM does *not*
> >> >> >>>> >> >> >> have any idea in how it should be flushing these:
> >> >> >>>> >> >> >>
> >> >> >>>> >> >> >> obj_a = A()
> >> >> >>>> >> >> >> obj_b = B()
> >> >> >>>> >> >> >>
> >> >> >>>> >> >> >> obj_a.some_fk = obj_b.some_id # ORM doesn't care
> about this, no
> >> >> >>>> >> >> >> ordering is implied
> >> >> >>>> >> >> >>
> >> >> >>>> >> >> >>
> >> >> >>>> >> >> >> since you said you're not setting any IDs, I'm not
> sure how you could
> >> >> >>>> >> >> >> be doing the above.
> >> >> >>>> >> >> >>
> >> >> >>>> >> >> >>
> >> >> >>>> >> >> >>
> >> >> >>>> >> >> >>
> >> >> >>>> >> >> >>
> >> >> >>>> >> >> >>
> >> >> >>>> >> >> >> On Tue, Sep 18, 2018 at 5:53 AM Simon King <
> si...@simonking.org.uk> wrote:
> >> >> >>>> >> >> >> >
> >> >> >>>> >> >> >> > It's not something I've ever looked into, but I'm
> not aware of any
> >> >> >>>> >> >> >> > debugging options here, no. You'd probably want to
> start by scattering
> >> >> >>>> >> >> >> > print statements around the UOWTransaction class
> >> >> >>>> >> >> >> > (
> https://bitbucket.org/zzzeek/sqlalchemy/src/c94d67892e68ac317d72eb202cca427084b3ca74/lib/sqlalchemy/orm/unitofwork.py?at=master&fileviewer=file-view-default#unitofwork.py-111
> )
> >> >> >>>> >> >> >> >
> >> >> >>>> >> >> >> > Looking at that code made me wonder whether you've
> set any particular
> >> >> >>>> >> >> >> > cascade options on your relationship; I'm not sure
> if cascade options
> >> >> >>>> >> >> >> > affect the dependency calculation.
> >> >> >>>> >> >> >> >
> >> >> >>>> >> >> >> > Simon
> >> >> >>>> >> >> >> >
> >> >> >>>> >> >> >> > On Tue, Sep 18, 2018 at 5:28 AM Alex Rothberg <
> agrot...@gmail.com> wrote:
> >> >> >>>> >> >> >> > >
> >> >> >>>> >> >> >> > > In order to guide me in stripping down this code
> to produce an example for positing, are there any options / flags /
> introspections I can turn on to understand how sql makes decisions about
> the order in which is writes statements to the DB?
> >> >> >>>> >> >> >> > >
> >> >> >>>> >> >> >> > > On Friday, September 14, 2018 at 10:13:45 AM
> UTC-4, Simon King wrote:
> >> >> >>>> >> >> >> > >>
> >> >> >>>> >> >> >> > >> In that case can you show us the code that is
> causing the problem?
> >> >> >>>> >> >> >> > >> On Fri, Sep 14, 2018 at 2:55 PM Alex Rothberg <
> agrot...@gmail.com> wrote:
> >> >> >>>> >> >> >> > >> >
> >> >> >>>> >> >> >> > >> > I am not generating any IDs myself and I
> already have relationships between the models.
> >> >> >>>> >> >> >> > >> >
> >> >> >>>> >> >> >> > >> > On Friday, September 14, 2018 at 4:33:08 AM
> UTC-4, Simon King wrote:
> >> >> >>>> >> >> >> > >> >>
> >> >> >>>> >> >> >> > >> >> On Thu, Sep 13, 2018 at 10:50 PM Alex Rothberg
> <agrot...@gmail.com> wrote:
> >> >> >>>> >> >> >> > >> >> >
> >> >> >>>> >> >> >> > >> >> > Is it possible to hint at sqla the order in
> which it should write out changes to the DB?
> >> >> >>>> >> >> >> > >> >> >
> >> >> >>>> >> >> >> > >> >> > I am having issues in which I add two new
> objects to a session, a and b where a depends on b, but sqla is flushing a
> before b leading to an fk issue. I can solve this a few ways: explicitly
> calling flush after adding b, or changing the fk constraint to be initially
> deferred. Ideally I would not have to do either of these.
> >> >> >>>> >> >> >> > >> >> >
> >> >> >>>> >> >> >> > >> >>
> >> >> >>>> >> >> >> > >> >> If you have configured a relationship between
> the two classes
> >> >> >>>> >> >> >> > >> >> (
> http://docs.sqlalchemy.org/en/latest/orm/tutorial.html#building-a-relationship
> ),
> >> >> >>>> >> >> >> > >> >> and you've linked the objects together using
> that relationship (a.b =
> >> >> >>>> >> >> >> > >> >> b), then SQLAlchemy will flush them in the
> correct order. If you are
> >> >> >>>> >> >> >> > >> >> generating your IDs in Python and assigning
> them to the primary and
> >> >> >>>> >> >> >> > >> >> foreign key columns directly, SQLAlchemy
> probably won't understand the
> >> >> >>>> >> >> >> > >> >> dependency.
> >> >> >>>> >> >> >> > >> >>
> >> >> >>>> >> >> >> > >> >> Does using a relationship fix your problem?
> >> >> >>>> >> >> >> > >> >>
> >> >> >>>> >> >> >> > >> >> Simon
> >> >> >>>> >> >> >> > >> >
> >> >> >>>> >> >> >> > >> > --
> >> >> >>>> >> >> >> > >> > 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
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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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> >> >> >>>> >> >> >> >
> >> >> >>>> >> >> >> > --
> >> >> >>>> >> >> >> > 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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> >> >> >>>> >> >>
> >> >> >>>> >> >> --
> >> >> >>>> >> >> 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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> >> >> >>>> >> > For more options, visit https://groups.google.com/d/optout
> .
> >> >> >>>> >
> >> >> >>>> > --
> >> >> >>>> > 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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> >> >
> >> > --
> >> > 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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> >> For more options, visit https://groups.google.com/d/optout.
> >
> > --
> > 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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> > For more options, visit https://groups.google.com/d/optout.
>
> --
> 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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