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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>>>
>>> .
>>
>>
>> --
>> 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
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] Assert contents of DB tables
Hello I would like to assert the contents of tables in my PG schema i.e. make sure it contains the data I'm expecting I am aware of various options: 1) Compare the actual and expected tables using a sql query, orchestrated by sqlalchemy (i.e. create the actual and expected tables in DB, run the sql comparison script, return the output) 2) Load the actual tables as tuples and compare them with expected tuples using something like assert_result https://github.com/sqlalchemy/sqlalchemy/blob/d933ddd503a1ca0a7c562c51c503139c541e707e/lib/sqlalchemy/testing/assertions.py#L465 3) Load the actual tables as dataframes and compare them with expected dataframes using pandas assert_frame_equal https://pandas.pydata.org/pandas-docs/stable/reference/api/pandas.testing.assert_frame_equal.html Any recommendations / thoughts would be much appreciated, both as to the approach and the implementation :-) -- 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/d786a59c-b995-4614-8023-bd27f20b2dee%40googlegroups.com.
