Column vs InstrumentedAttribute

[Val Huber]

Hello, All

In SQLAlchemy 1.4.29, the I get the warnings shown in the attached screen shot.  These are calls to LogicBank; if I alter LogicBank to use Column instead of InstrumentedAttribute, it fails with 

AttributeError: Neither 'InstrumentedAttribute' object nor 'Comparator' object associated with Customer.Balance has an attribute 'descriptor'

I don't believe I got these warnings with SQLAlchemy 1.3.

Suggestions?

Thanks,

Val

[Val Huber]

The target function looks like this:

class Rule:

"""Invoke these functions to declare rules.

Rules are *not* run as they are defined,

they are run when you issue `session.commit()'.

.. _Rule Summary:

https://github.com/valhuber/LogicBank/wiki/Rule-Summary

Use code completion to discover rules and their parameters.

"""

@staticmethod

def sum(derive: InstrumentedAttribute, as_sum_of: any, where: any = None, child_role_name: str = ""):

"""

Derive parent column as sum of designated child column, optional where

Example

Rule.sum(derive=models.Customer.Balance, as_sum_of=models.Order.AmountTotal,

where=Lambda row: row.ShippedDate is None)

Optimized to eliminate / minimize SQLs: Pruning, Adjustment Logic

Args:

derive: name of parent <class.attribute> being derived

as_sum_of: name of child <class.attribute> being summed

child_role_name: parent's child accessor attribute (required only for disambiguation)

where: optional where clause, designates which child rows are summed

"""

return Sum(derive, as_sum_of, where, child_role_name)

The model is declared like this:

class Customer(SAFRSBase, Base):

__tablename__ = 'Customer'

_s_collection_name = 'Customer'

__bind_key__ = 'None'

Id = Column(String(8000), primary_key=True)

CompanyName = Column(String(8000))

Balance = Column(DECIMAL)

[Mike Bayer]

those are typing issues being reported by Pylance and do not affect the runtime behavior of the application.

Pylance refers to typing stubs for SQLAlchemy 1.4 which don't apply to SQLAlchemy 1.3.

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Attachments:

• Column vs InstumentedAttribute.png
  

[Val Huber]

Yes, Mike, I agree -  definitely seeing correct runtime behavior.

Just looking to get past the somewhat scary alerts (which, btw, do not occur in PyCharm).  Care and feeding of the IDE, I suppose…

Not super urgent, but would be good to clear up...

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[Mike Bayer]

your "derive" argument would need to be opened up to accept ColumnElement.

if you are going for being fully typed like this you would do way better by targeting 2.0 instead of 1.4.  the typing in 1.4 is nor very good and also not compatible with that of 2.0.

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