On Wed, Aug 4, 2021 at 12:30 PM Larry Martell <[email protected]> wrote:
>
> On Tue, Aug 3, 2021 at 11:11 PM Lele Gaifax <[email protected]> wrote:
> >
> > Larry Martell <[email protected]> writes:
> >
> > > I am trying to write a function that takes kwargs as a param and
> > > generates an update statement where the rows to be updated are
> > > specified in an in clause.
> > >
> > > Something like this:
> > >
> > > def update_by_in(self, **kwargs):
> > > filter_group = []
> > > for col in kwargs['query_params']:
> > > # obviously this line does not work as col is a string,
> > > but this is the intent
> > >
> > > filter_group.append(col.in_(tuple(kwargs['query_params'][col])))
> > >
> > >
> > > self._session.query(self.model_class).filter(*filter_group).update(kwargs['values'])
> > >
> > > self.update_by_in(
> > > **{'query_params': {'companyCode': ['A', 'B', 'C']},
> > > 'values': {'portfolioName': 'test'}}
> > > )
> > >
> > > Is there a way to do this?
> >
> > Sure, and easy enough: replace the line where you append to `filter_group`
> > with something like
> >
> > attr = getattr(self.model_class, col)
> > filter_group.append(attr.in_(tuple(kwargs['query_params'][col])))
> >
> > that is, obtain the mapped class member named after "col", and use that to
> > build the filter expression.
>
> Thanks for the reply. When I do that, filter group ends up like:
>
> print(type(filter_group[0]))
>
> <class 'sqlalchemy.sql.elements.BinaryExpression'>
>
> print(filter_group[0])
>
> dbo."Portfolio"."companyCode" IN (:companyCode_1, :companyCode_2,
> :companyCode_3)
>
> Which then fails with:
>
> sqlalchemy.orm.evaluator.UnevaluatableError: Cannot evaluate
> clauselist with operator <function comma_op at 0x7f632f8f3dc0>
>
> I am passing in:
>
> **{'query_params': {'companyCode': ['A', 'B', 'C']},
> 'values': {'portfolioName': 'test'}}
>
> Any ideas how to get past this?
I found the issue was not from the select but from the update. But I
can't seem to get that to work. Here is my code now (to remove any
questions about the arg passing to update I hard coded for testing):
filter_group = []
for col in kwargs['query_params']:
attr = getattr(self.model_class, col)
filter_group.append(attr.in_(tuple(kwargs['query_params'][col])))
self._session.query(self.model_class).\
filter(*filter_group).\
update({'Portfolio.portfolioName': 'xxxx'})
This gives:
sqlalchemy.orm.evaluator.UnevaluatableError: Cannot evaluate
clauselist with operator <function comma_op at 0x7f33f037adc0>
To verify the query part is working I printed out the return from
self._session.query(self.model_class).filter(*filter_group).all()
[<common.models_dec_core.Portfolio object at 0x7f2b98157f40>]
What am I doing wrong here?
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