May I add an extra overload for the select function, for 5 arguments, or is there a reason for this limit?

[GiorgioPorgio]

First Check

• I added a very descriptive title here.
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• I already checked if it is not related to SQLModel but to SQLAlchemy.

Commit to Help

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Example Code

from sqlmodel import select
from my_models import User, Comments, Preferences, Likes, Wishlist

# No overloads for "select" match the provided arguments: ...
# Would type fine for 1-4 arguments
query = select(User, Comments, Preferences, Likes, Wishlist)

Description

I am trying to write a select statement that selects 5 different SQLModel children. However I get a type error as the overloads for select are limited to 4.

Other people have had this issue too, eg here. The fix seems to be to fallback to SQLAlchemy, but then we lost the beautiful typing of SQLModel.

I am happy to fix this problem by adding extra overloads. Or is there some reason this is capped to 4? Thank you very much and I'll do my best to push the help forward!

Operating System

macOS

Operating System Details

No response

SQLModel Version

0.0.22

Python Version

3.11.9

Additional Context

No response

[marvinth01]

Seems like it would even be as trivial as just increasing the following and then regenerating the source file:

sqlmodel/scripts/generate_select.py

Line 16 in 7d00768

number_of_types = 4

Might as well go up to like 10 or 20 since it's just autogenerated at no additional effort.

[jbethune]

This is really confusing behaviour. I was double-checking all of my tables to see if I was missing some definition until I figured out that the total number of tables in the select() call is the problem. It would help to document this better and explain why this constraint exists and what other (better?) options there are to query a lot of tables at once in SQLModel.

[GiorgioPorgio]

There are technical reasons for this limitation turns out, stemming from Python's type system. I've opened a PR to at least increase it to 5 :)

[jbethune]

The docstring does not document this limitation:

from sqlmodel import select
help(select)

Help on function select in module sqlmodel.sql._expression_select_gen:

select(*entities: Any) -> Union[sqlmodel.sql._expression_select_cls.Select, sqlmodel.sql._expression_select_cls.SelectOfScalar]

It looks like select accepts an arbitary number of arguments, which isn't correct.