Re: [sqlalchemy] Deletion of object with relationship(lazy='raise')
I can confirm this is a bug as I've found precedent for this not having to
raise, new issue is
https://github.com/sqlalchemy/sqlalchemy/issues/4997
On Fri, Nov 22, 2019, at 9:24 AM, Mike Bayer wrote:
> that said, I'm looking at this as a potential bug because it should be able
> to leave this attribute alone, not really sure how this should be handled.
>
> On Fri, Nov 22, 2019, at 9:21 AM, Mike Bayer wrote:
>> lazy="raise" on a many to one is problematic because a lot of many-to-one
>> operations involve pulling up the object from the identity map, and that's
>> it. since people are usually only trying to guard against SQL being emitted,
>> use the raise_on_sql option instead:
>>
>> parent = relationship(Parent, lazy='raise_on_sql')
>>
>> thanks for the perfect test case BTW makes this very easy for me
>>
>> On Fri, Nov 22, 2019, at 6:12 AM, Marat Sharafutdinov wrote:
>>> from sqlalchemy import Column, ForeignKey, Integer, create_engine
>>> from sqlalchemy.ext.declarative import declarative_base
>>> from sqlalchemy.orm import relationship, sessionmaker
>>>
>>> Base = declarative_base()
>>>
>>> class Parent(Base):
>>> __tablename__ = 'parents'
>>> id = Column(Integer, primary_key=True)
>>>
>>> class Child(Base):
>>> __tablename__ = 'children'
>>> id = Column(Integer, primary_key=True)
>>> parent_id = Column(Integer, ForeignKey(Parent.id))
>>> parent = relationship(Parent, lazy='raise', passive_deletes=True)
>>>
>>> engine = create_engine('sqlite:///:memory:', echo=True)
>>> Base.metadata.create_all(engine)
>>> Session = sessionmaker(bind=engine)
>>> session = Session()
>>>
>>> # Add
>>> parent = Parent()
>>> session.add(parent)
>>> session.flush()
>>> child = Child(parent_id=parent.id)
>>> session.add(child)
>>> session.commit()
>>>
>>> # Delete
>>> child = session.query(Child).first()
>>> session.delete(child)
>>> session.commit()
>>>
>>> Now I'm getting the following warning:
>>> /.venv/lib/python3.8/site-packages/sqlalchemy/orm/relationships.py:2021:
>>> SAWarning: On Child.parent, 'passive_deletes' is normally configured on
>>> one-to-many, one-to-one, many-to-many relationships only.
>>>
>>> If I change `parent` relationship as follows:
>>> parent = relationship(Parent, lazy='raise', backref=backref('children',
>>> passive_deletes=True))
>>> then I would get the following exception:
>>> sqlalchemy.exc.InvalidRequestError: 'Child.parent' is not available due to
>>> lazy='raise'
>>>
>>> How should it be made properly?
>>>
>>> --
>>> 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.
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>>> email to sqlalchemy+unsubscr...@googlegroups.com.
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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.
> ---
> You received this message because you are subscribed to the Google Groups
> "sqlalchemy" group.
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>
> .
--
SQLAlchemy -
The Python SQL Toolkit
Re: [sqlalchemy] Deletion of object with relationship(lazy='raise')
that said, I'm looking at this as a potential bug because it should be able to
leave this attribute alone, not really sure how this should be handled.
On Fri, Nov 22, 2019, at 9:21 AM, Mike Bayer wrote:
> lazy="raise" on a many to one is problematic because a lot of many-to-one
> operations involve pulling up the object from the identity map, and that's
> it. since people are usually only trying to guard against SQL being emitted,
> use the raise_on_sql option instead:
>
> parent = relationship(Parent, lazy='raise_on_sql')
>
> thanks for the perfect test case BTW makes this very easy for me
>
> On Fri, Nov 22, 2019, at 6:12 AM, Marat Sharafutdinov wrote:
>> from sqlalchemy import Column, ForeignKey, Integer, create_engine
>> from sqlalchemy.ext.declarative import declarative_base
>> from sqlalchemy.orm import relationship, sessionmaker
>>
>> Base = declarative_base()
>>
>> class Parent(Base):
>> __tablename__ = 'parents'
>> id = Column(Integer, primary_key=True)
>>
>> class Child(Base):
>> __tablename__ = 'children'
>> id = Column(Integer, primary_key=True)
>> parent_id = Column(Integer, ForeignKey(Parent.id))
>> parent = relationship(Parent, lazy='raise', passive_deletes=True)
>>
>> engine = create_engine('sqlite:///:memory:', echo=True)
>> Base.metadata.create_all(engine)
>> Session = sessionmaker(bind=engine)
>> session = Session()
>>
>> # Add
>> parent = Parent()
>> session.add(parent)
>> session.flush()
>> child = Child(parent_id=parent.id)
>> session.add(child)
>> session.commit()
>>
>> # Delete
>> child = session.query(Child).first()
>> session.delete(child)
>> session.commit()
>>
>> Now I'm getting the following warning:
>> /.venv/lib/python3.8/site-packages/sqlalchemy/orm/relationships.py:2021:
>> SAWarning: On Child.parent, 'passive_deletes' is normally configured on
>> one-to-many, one-to-one, many-to-many relationships only.
>>
>> If I change `parent` relationship as follows:
>> parent = relationship(Parent, lazy='raise', backref=backref('children',
>> passive_deletes=True))
>> then I would get the following exception:
>> sqlalchemy.exc.InvalidRequestError: 'Child.parent' is not available due to
>> lazy='raise'
>>
>> How should it be made properly?
>>
>> --
>> 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/40f63feb-383e-4fee-8db6-21a757887c54%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.
> ---
> 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/79e8c08e-c761-4d48-96d8-4cabf6de36de%40www.fastmail.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] Deletion of object with relationship(lazy='raise')
lazy="raise" on a many to one is problematic because a lot of many-to-one
operations involve pulling up the object from the identity map, and that's it.
since people are usually only trying to guard against SQL being emitted, use
the raise_on_sql option instead:
parent = relationship(Parent, lazy='raise_on_sql')
thanks for the perfect test case BTW makes this very easy for me
On Fri, Nov 22, 2019, at 6:12 AM, Marat Sharafutdinov wrote:
> from sqlalchemy import Column, ForeignKey, Integer, create_engine
> from sqlalchemy.ext.declarative import declarative_base
> from sqlalchemy.orm import relationship, sessionmaker
>
> Base = declarative_base()
>
> class Parent(Base):
> __tablename__ = 'parents'
> id = Column(Integer, primary_key=True)
>
> class Child(Base):
> __tablename__ = 'children'
> id = Column(Integer, primary_key=True)
> parent_id = Column(Integer, ForeignKey(Parent.id))
> parent = relationship(Parent, lazy='raise', passive_deletes=True)
>
> engine = create_engine('sqlite:///:memory:', echo=True)
> Base.metadata.create_all(engine)
> Session = sessionmaker(bind=engine)
> session = Session()
>
> # Add
> parent = Parent()
> session.add(parent)
> session.flush()
> child = Child(parent_id=parent.id)
> session.add(child)
> session.commit()
>
> # Delete
> child = session.query(Child).first()
> session.delete(child)
> session.commit()
>
> Now I'm getting the following warning:
> /.venv/lib/python3.8/site-packages/sqlalchemy/orm/relationships.py:2021:
> SAWarning: On Child.parent, 'passive_deletes' is normally configured on
> one-to-many, one-to-one, many-to-many relationships only.
>
> If I change `parent` relationship as follows:
> parent = relationship(Parent, lazy='raise', backref=backref('children',
> passive_deletes=True))
> then I would get the following exception:
> sqlalchemy.exc.InvalidRequestError: 'Child.parent' is not available due to
> lazy='raise'
>
> How should it be made properly?
>
> --
> 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/40f63feb-383e-4fee-8db6-21a757887c54%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.
---
You received this message because you are subscribed to the Google Groups
"sqlalchemy" group.
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[sqlalchemy] Deletion of object with relationship(lazy='raise')
from sqlalchemy import Column, ForeignKey, Integer, create_engine
from sqlalchemy.ext.declarative import declarative_base
from sqlalchemy.orm import relationship, sessionmaker
Base = declarative_base()
class Parent(Base):
__tablename__ = 'parents'
id = Column(Integer, primary_key=True)
class Child(Base):
__tablename__ = 'children'
id = Column(Integer, primary_key=True)
parent_id = Column(Integer, ForeignKey(Parent.id))
parent = relationship(Parent, lazy='raise', passive_deletes=True)
engine = create_engine('sqlite:///:memory:', echo=True)
Base.metadata.create_all(engine)
Session = sessionmaker(bind=engine)
session = Session()
# Add
parent = Parent()
session.add(parent)
session.flush()
child = Child(parent_id=parent.id)
session.add(child)
session.commit()
# Delete
child = session.query(Child).first()
session.delete(child)
session.commit()
Now I'm getting the following warning:
/.venv/lib/python3.8/site-packages/sqlalchemy/orm/relationships.py:2021:
SAWarning: On Child.parent, 'passive_deletes' is normally configured on one-
to-many, one-to-one, many-to-many relationships only.
If I change `parent` relationship as follows:
parent = relationship(Parent, lazy='raise', backref=backref('children',
passive_deletes=True))
then I would get the following exception:
sqlalchemy.exc.InvalidRequestError: 'Child.parent' is not available due to
lazy='raise'
How should it be made properly?
--
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" group.
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To view this discussion on the web visit
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