[sqlalchemy] AttributeError: Neither 'QueryableAttribute' object nor 'Comparator' object has an attribute '__visit_name__'
I am using SQLAlchemy 1.4.2 and have been encountering this strange error
message which I've managed to boil down to this minimal example:
import sqlalchemy as sa
from sqlalchemy.orm import declarative_base, relationship
Base = declarative_base()
class Parent(Base):
__tablename__ = "parent"
id = sa.Column(sa.Integer, primary_key=True)
class Child(Base):
__tablename__ = "child"
id = sa.Column(sa.Integer, primary_key=True)
parent_id = sa.Column(sa.Integer, sa.ForeignKey("parent.id"))
parent = relationship("Parent")
statement = sa.select([Child.id]).join(Child.parent).where(Parent.id ==
sa.bindparam("id"))
statement = statement.params(id=10)
The call to statement.params(...) is throwing the following stacktrace. Can
anyone tell me what I'm doing wrong?
Traceback (most recent call last):
File "test_sqlalchemy_error.py", line 20, in
statement = statement.params(id=10)
File ".venv/lib/python3.7/site-packages/sqlalchemy/sql/elements.py", line
346, in params
return self._replace_params(False, optionaldict, kwargs)
File ".venv/lib/python3.7/site-packages/sqlalchemy/sql/elements.py", line
363, in _replace_params
return cloned_traverse(self, {}, {"bindparam": visit_bindparam})
File ".venv/lib/python3.7/site-packages/sqlalchemy/sql/visitors.py", line
742, in cloned_traverse
obj = clone(obj, deferred_copy_internals=deferred_copy_internals)
File ".venv/lib/python3.7/site-packages/sqlalchemy/sql/visitors.py", line
735, in clone
newelem._copy_internals(clone=clone, **kw)
File ".venv/lib/python3.7/site-packages/sqlalchemy/sql/selectable.py",
line 5208, in _copy_internals
clone=clone, omit_attrs=("_from_obj",), **kw
File ".venv/lib/python3.7/site-packages/sqlalchemy/sql/traversals.py",
line 718, in _copy_internals
result = meth(attrname, self, obj, **kw)
File ".venv/lib/python3.7/site-packages/sqlalchemy/sql/traversals.py",
line 777, in visit_setup_join_tuple
for (target, onclause, from_, flags) in element
File ".venv/lib/python3.7/site-packages/sqlalchemy/sql/traversals.py",
line 777, in
for (target, onclause, from_, flags) in element
File ".venv/lib/python3.7/site-packages/sqlalchemy/sql/visitors.py", line
736, in clone
meth = visitors.get(newelem.__visit_name__, None)
File ".venv/lib/python3.7/site-packages/sqlalchemy/orm/attributes.py",
line 308, in __getattr__
replace_context=err,
File ".venv/lib/python3.7/site-packages/sqlalchemy/util/compat.py", line
198, in raise_
raise exception
AttributeError: Neither 'QueryableAttribute' object nor 'Comparator' object
associated with Child.parent has an attribute '__visit_name__'
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Re: [sqlalchemy] Injecting User info into _history table to track who performed the change
It seems I lost my previous email.. Here it is again:
Sure !
Here are 2 classes for which the generated _history sister tables
(generated by history_meta.py) throw the warnings:
*The Parent class:*
class Process(Versioned, Base, UtilityMixin):
__tablename__ = 'process'
__table_args__ = {}
id = Column(Integer, primary_key=True)
discriminator = Column('type', String(64))
timestamp = Column(DateTime, nullable=False)
start_date = Column(Date, nullable=False)
am_pm = Column(String(8))
probable_end_date = Column(Date)
end_date = Column(Date)
user = Column(String(128), nullable=False)
comments = Column(Text)
__mapper_args__ = {'polymorphic_on': discriminator, 'polymorphic_identity':
'process',
'order_by': [start_date.desc(), id.desc()]}
protocol_id = Column(Integer, ForeignKey('protocol.id', onupdate='cascade',
ondelete='restrict'))
process_type_id = Column(Integer, ForeignKey('process_type.id',
onupdate='cascade',
ondelete='restrict'))
protocol = relationship(Protocol, backref='processes', uselist=False)
process_type = relationship(ProcessType, backref='processes', uselist=False)
*The Child class:*
class CompoundAdministration(Process):
__tablename__ = 'compound_administration'
__table_args__ = {}
__mapper_args__ = {'polymorphic_identity': 'compound_admin'}
id = Column(Integer, ForeignKey('process.id', onupdate='cascade',
ondelete='cascade'),
primary_key=True)
dose = Column(String(64))
substance = Column(String(128))
frequency = Column(String(64))
duration = Column(String(64))
route_id = Column(Integer, ForeignKey('administration_route.id',
onupdate='cascade',
ondelete='restrict'))
route = relationship(AdministrationRoute, uselist=False)
As reminder, versioning was implemented using this recipe/example from SQLA:
https://docs.sqlalchemy.org/en/13/_modules/examples/versioned_history/history_meta.html
And here is the associated warning:
SAWarning:
Implicitly combining column process_history.user with column
compound_administration_history.user under attribute 'user'.
Please configure one or more attributes for these same-named columns
explicitly.
Thanks for your help resolving this,
JP
On Tuesday, March 23, 2021 at 6:24:03 a.m. UTC-4 Simon King wrote:
> Can you show us the mapping definitions that are triggering these warnings?
>
> On Mon, Mar 22, 2021 at 6:29 PM JPLaverdure wrote:
> >
> > Hi,
> >
> > Thanks for your support guys.
> >
> > I've implemented logging the user's email in the _history tables by
> adding this Column definition inside my history_meta.py file:
> > cols.append(
> > Column(
> > "user",
> > String,
> > info=version_meta,
> > )
> > )
> > but i'm running into a good load of SAWarnings stating that there is an
> implicit combining of the "user" column taking place
> > (I have multi-table inheritance setup for some entities, those are the
> ones throwing the warning)
> > I don't get why the column "changed" (which holds the timestamp of the
> change) and is defined in exactly the same way does not generate these
> warnings ?
> > What configuration setting am I missing here ?
> >
> > I found this
> >
> https://docs.sqlalchemy.org/en/13/faq/ormconfiguration.html#i-m-getting-a-warning-or-error-about-implicitly-combining-column-x-under-attribute-y
> > But it doesn't seem to fit 100% with what I'm seeing inside
> history_meta.py
> >
> > Thanks !!
> > On Monday, March 15, 2021 at 4:33:40 p.m. UTC-4 Jonathan Vanasco wrote:
> >>
> >> Going beyond what Simon did..
> >>
> >> I typically make make a table like `user_transaction`, which has all of
> the relevant information for the transaction:
> >>
> >> * User ID
> >> * Timestamp
> >> * Remote IP
> >>
> >> Using the sqlalchemy hooks, I'll then do something like:
> >>
> >> * update the object table with the user_transaction id
> >> or
> >> * use an association table that tracks a user_transaction_id to an
> object id and version
> >>
> >> FYI, Simon -- as of a few weeks ago, that pattern is now part of the
> pyramid sqlalchemy starter template!
> >>
> >> On Monday, March 15, 2021 at 6:46:02 AM UTC-4 Simon King wrote:
> >>>
> >>> I use pyramid as a web framework, and when I create the DB session for
> >>> each request, I add a reference to the current request object to the
> >>> DB session. The session object has an "info" attribute which is
> >>> intended for application-specific things like this:
> >>>
> >>>
> https://docs.sqlalchemy.org/en/13/orm/session_api.html#sqlalchemy.orm.session.Session.info
> >>>
> >>> Then, in the before_flush event handler, I retrieve the request object
> >>> from session.info, and then I can add whatever request-specific info I
> >>> want to the DB.
> >>>
> >>> Simon
> >>>
> >>> On Sun, Mar 14, 2021 at 4:05 PM JPLaverdure
> wrote:
> >>> >
> >>> > Hi Elmer,
> >>> >
> >>> > Thanks for your reply !
> >>> > My issue is not with obtaining the info I want to inject (the logged
> in users's email), I already have that all ready to go :)
> >>> >
> >>> > My whole database is versioned using
Re: [sqlalchemy] Injecting User info into _history table to track who performed the change
Can you show us the mapping definitions that are triggering these warnings? On Mon, Mar 22, 2021 at 6:29 PM JPLaverdure wrote: > > Hi, > > Thanks for your support guys. > > I've implemented logging the user's email in the _history tables by adding > this Column definition inside my history_meta.py file: > cols.append( > Column( > "user", > String, > info=version_meta, > ) > ) > but i'm running into a good load of SAWarnings stating that there is an > implicit combining of the "user" column taking place > (I have multi-table inheritance setup for some entities, those are the ones > throwing the warning) > I don't get why the column "changed" (which holds the timestamp of the > change) and is defined in exactly the same way does not generate these > warnings ? > What configuration setting am I missing here ? > > I found this > https://docs.sqlalchemy.org/en/13/faq/ormconfiguration.html#i-m-getting-a-warning-or-error-about-implicitly-combining-column-x-under-attribute-y > But it doesn't seem to fit 100% with what I'm seeing inside history_meta.py > > Thanks !! > On Monday, March 15, 2021 at 4:33:40 p.m. UTC-4 Jonathan Vanasco wrote: >> >> Going beyond what Simon did.. >> >> I typically make make a table like `user_transaction`, which has all of the >> relevant information for the transaction: >> >> * User ID >> * Timestamp >> * Remote IP >> >> Using the sqlalchemy hooks, I'll then do something like: >> >> * update the object table with the user_transaction id >> or >> * use an association table that tracks a user_transaction_id to an object id >> and version >> >> FYI, Simon -- as of a few weeks ago, that pattern is now part of the pyramid >> sqlalchemy starter template! >> >> On Monday, March 15, 2021 at 6:46:02 AM UTC-4 Simon King wrote: >>> >>> I use pyramid as a web framework, and when I create the DB session for >>> each request, I add a reference to the current request object to the >>> DB session. The session object has an "info" attribute which is >>> intended for application-specific things like this: >>> >>> https://docs.sqlalchemy.org/en/13/orm/session_api.html#sqlalchemy.orm.session.Session.info >>> >>> Then, in the before_flush event handler, I retrieve the request object >>> from session.info, and then I can add whatever request-specific info I >>> want to the DB. >>> >>> Simon >>> >>> On Sun, Mar 14, 2021 at 4:05 PM JPLaverdure wrote: >>> > >>> > Hi Elmer, >>> > >>> > Thanks for your reply ! >>> > My issue is not with obtaining the info I want to inject (the logged in >>> > users's email), I already have that all ready to go :) >>> > >>> > My whole database is versioned using the history_meta.py example from >>> > SQLAlchemy >>> > https://docs.sqlalchemy.org/en/13/_modules/examples/versioned_history/history_meta.html >>> > >>> > I was hoping for a simple way to inject the user info into the _history >>> > row creation steps. >>> > >>> > The SQLAlchemy example makes use of this event listener: >>> > >>> > def versioned_session(session): >>> > >>> > @event.listens_for(session, "before_flush") >>> > def before_flush(session, flush_context, instances): >>> > for obj in versioned_objects(session.dirty): >>> > create_version(obj, session) >>> > for obj in versioned_objects(session.deleted): >>> > create_version(obj, session, deleted=True) >>> > >>> > So I'm tempted to follow the same strategy and just override this >>> > listener to supplement it with the user info but I'm wondering how to >>> > pass in non SQLAlchemy info into its execution context... >>> > >>> > So basically, I have the info I want to inject, I'm just not sure how to >>> > pass it to SQLAlchemy >>> > >>> > Thanks, >>> > >>> > JP >>> > >>> > On Friday, March 12, 2021 at 6:55:19 p.m. UTC-5 elmer@gmail.com wrote: >>> >> >>> >> Hi JP, >>> >> >>> >> Depending on how you've implemented your history tracking, that routine >>> >> is quite far removed from your web framework and getting a neat, clean >>> >> way of dealing with that might not be within reach. >>> >> >>> >> However, most web frameworks have some concept of a threadlocal request >>> >> (or function to retrieve it), which you could invoke and if such a >>> >> request exists, you could use that to load whatever user identity you >>> >> have available on there (again, the details differ, but this tends to be >>> >> a shared feature). From there you can store the user either as a foreign >>> >> key, or a unique identifier like email. Which one you pick would depend >>> >> on how you want the history to be affected when you delete a user record >>> >> for example. >>> >> >>> >> >>> >> >>> >> On Fri, Mar 12, 2021 at 11:58 PM JPLaverdure wrote: >>> >>> >>> >>> Hello everyone, >>> >>> >>> >>> We already have the ability to timestamp the creation of the history >>> >>> row, but it would also be interesting to be able to track the user >>> >>> responsible for the content update. >>> >>> I would like to get suggestions on the best way to
