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 receiving
>> >> >>>> >> >> >> > >> > emails from it, send an email to
>> >> >>>> >> >> >> > >> > sqlalchemy+...@googlegroups.com.
>> >> >>>> >> >> >> > >> > To post to this group, send email to
>> >> >>>> >> >> >> > >> > sqlal...@googlegroups.com.
>> >> >>>> >> >> >> > >> > Visit this group at
>> >> >>>> >> >> >> > >> > https://groups.google.com/group/sqlalchemy.
>> >> >>>> >> >> >> > >> > 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.
>> >> >>>> >> >> >> > > ---
>> >> >>>> >> >> >> > > 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+...@googlegroups.com.
>> >> >>>> >> >> >> > > To post to this group, send email to
>> >> >>>> >> >> >> > > sqlal...@googlegroups.com.
>> >> >>>> >> >> >> > > Visit this group at
>> >> >>>> >> >> >> > > https://groups.google.com/group/sqlalchemy.
>> >> >>>> >> >> >> > > 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.
>> >> >>>> >> >> >> > ---
>> >> >>>> >> >> >> > 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+...@googlegroups.com.
>> >> >>>> >> >> >> > To post to this group, send email to
>> >> >>>> >> >> >> > sqlal...@googlegroups.com.
>> >> >>>> >> >> >> > Visit this group at
>> >> >>>> >> >> >> > https://groups.google.com/group/sqlalchemy.
>> >> >>>> >> >> >> > 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.
>> >> >>>> >> >> > ---
>> >> >>>> >> >> > 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+...@googlegroups.com.
>> >> >>>> >> >> > To post to this group, send email to
>> >> >>>> >> >> > sqlal...@googlegroups.com.
>> >> >>>> >> >> > Visit this group at
>> >> >>>> >> >> > https://groups.google.com/group/sqlalchemy.
>> >> >>>> >> >> > 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.
>> >> >>>> >> >> ---
>> >> >>>> >> >> You received this message because you are subscribed to a
>> >> >>>> >> >> topic in the Google Groups "sqlalchemy" group.
>> >> >>>> >> >> To unsubscribe from this topic, visit
>> >> >>>> >> >> https://groups.google.com/d/topic/sqlalchemy/fZMJQoI2qkY/unsubscribe.
>> >> >>>> >> >> To unsubscribe from this group and all its topics, send an
>> >> >>>> >> >> email to sqlalchemy+...@googlegroups.com.
>> >> >>>> >> >> To post to this group, send email to sqlal...@googlegroups.com.
>> >> >>>> >> >> Visit this group at https://groups.google.com/group/sqlalchemy.
>> >> >>>> >> >> 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.
>> >> >>>> >> > ---
>> >> >>>> >> > 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+...@googlegroups.com.
>> >> >>>> >> > To post to this group, send email to sqlal...@googlegroups.com.
>> >> >>>> >> > Visit this group at https://groups.google.com/group/sqlalchemy.
>> >> >>>> >> > 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.
>> >> >>>> > ---
>> >> >>>> > 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+...@googlegroups.com.
>> >> >>>> > To post to this group, send email to sqlal...@googlegroups.com.
>> >> >>>> > Visit this group at https://groups.google.com/group/sqlalchemy.
>> >> >>>> > 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.
>> >> > ---
>> >> > 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+...@googlegroups.com.
>> >> > To post to this group, send email to sqlal...@googlegroups.com.
>> >> > Visit this group at https://groups.google.com/group/sqlalchemy.
>> >> > 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.
>> > ---
>> > 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 post to this group, send email to sqlalchemy@googlegroups.com.
>> > Visit this group at https://groups.google.com/group/sqlalchemy.
>> > 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.
>> ---
>> You received this message because you are subscribed to a topic in the
>> Google Groups "sqlalchemy" group.
>> To unsubscribe from this topic, visit
>> https://groups.google.com/d/topic/sqlalchemy/fZMJQoI2qkY/unsubscribe.
>> To unsubscribe from this group and all its topics, send an email to
>> sqlalchemy+unsubscr...@googlegroups.com.
>> To post to this group, send email to sqlalchemy@googlegroups.com.
>> Visit this group at https://groups.google.com/group/sqlalchemy.
>> 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.
> ---
> 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 post to this group, send email to sqlalchemy@googlegroups.com.
> Visit this group at https://groups.google.com/group/sqlalchemy.
> 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.
---
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 post to this group, send email to sqlalchemy@googlegroups.com.
Visit this group at https://groups.google.com/group/sqlalchemy.
For more options, visit https://groups.google.com/d/optout.
