Generation of typesystem classes from orm/sqlalchemy models (On-the-fly or command based)

[sandys]

hi,
i may be wrong here, but the code in https://github.com/encode/hostedapi/blob/26e5ea6713f7d33433ca5ff962353fbffa6e88be/source/datasource.py is actually parsing sqlalchemy models and creating typesystem classes from them.

can this functionality be made part of typesystem and have starlette use it ? so that we dont create two models (one for sqlalchemy and one for types).