feat(python): Support use of SQLAlchemy "Connectable" in write_database

[phi-friday]

pandas supports sa.engine.Connectable.
Passing sa.engine.Connectable allows the user to control the transaction.

[codecov]

Codecov Report

Attention: Patch coverage is 57.14286% with 3 lines in your changes missing coverage. Please review.

Project coverage is 80.49%. Comparing base (ad836bd) to head (7c5ae5e).
Report is 1 commits behind head on main.

Files	Patch %	Lines
py-polars/polars/dataframe/frame.py	57.14%	2 Missing and 1 partial ⚠️

Additional details and impacted files

@@            Coverage Diff             @@
##             main   #17470      +/-   ##
==========================================
- Coverage   80.49%   80.49%   -0.01%     
==========================================
  Files        1483     1483              
  Lines      195010   195013       +3     
  Branches     2781     2782       +1     
==========================================
- Hits       156972   156969       -3     
- Misses      37527    37532       +5     
- Partials      511      512       +1     

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[alexander-beedie]

I will double-check tonight (on mobile at the moment), but from what I can see this looks like a good addition; thanks!

[alexander-beedie]

Let's version-gate the tests, as they don't work on earlier versions of SQLAlchemy. (I will typically run DB tests with both versions locally, as not everyone has moved to v2.0 yet). The two suggested changes also require the additional import from polars._utils.various import parse_version at the top of the test module.

Otherwise, looks good to me 👍

[phi-friday]

Since it's entirely up to the user to control the transaction, I decided it was okay to just modify the test.

[phi-friday]

This is unrelated to this pr, but when I lowered the versions of sqlalchemy<2 and pandas<2.2, I got 3 errors.

FAILED tests/unit/interchange/test_roundtrip.py::test_from_dataframe_pandas_timestamp_ns - AssertionError: DataFrames are different (value mismatch for column 'a')
FAILED tests/unit/io/database/test_read.py::test_read_database_parameterised - sqlalchemy.exc.RemovedIn20Warning: Deprecated API features detected! These feature(s) are not co...
ERROR tests/unit/io/database/test_async.py

I know that async_sessionmaker can be replaced with sessionmaker starting with a certain version, but I don't remember which version.

[alexander-beedie]

Since it's entirely up to the user to control the transaction, I decided it was okay to just modify the test.

Even better; we'll have coverage for both versions ;)