hi -
that's a bug! The .params() method is kind of forgotten.
https://github.com/sqlalchemy/sqlalchemy/issues/6124 is added, however this is
not a regression since this is using new functionality on select(). I think I
have a fairly straightforward fix for this however it won't be in SQLAlchemy
1.4.3, which needs to go out very soon.
For now I would advise sending the params directly to the session.execute()
method.
On Tue, Mar 23, 2021, at 9:35 PM, Dane K Barney wrote:
> 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 <module>
> 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 <genexpr>
> 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__'
>
>
>
> --
> SQLAlchemy -
> The Python SQL Toolkit and Object Relational Mapper
>
> http://www.sqlalchemy.org/
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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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