[nerdponx]

As far as I know, there is zero or close to zero shared code.

PEP 249 is great to have, and it's nice to at least have a starting point for learning a new database connector library.

But not all database connector libraries implement the specification. One well-known library [0] explicitly and deliberately violates the spec with no spec-compliant "escape hatch". Also the style of passing parameters as a single sequence (e.g. list or tuple) tends to be a newbie trap, and having 4 different placeholder styles can be annoying.

That said, there are ODBC connector libraries [1] if you really do need a uniform interface. But at that point you might be better off with the SQLAlchemy "Core" query builder [2].

[0]: Asyncpg, https://magicstack.github.io/asyncpg/

[1]: https://wiki.python.org/moin/ODBC

[2]: https://docs.sqlalchemy.org/en/14/core/