There are currently some dialects and DBAPI modules that are not fully supported by SQLAlchemy. This is mainly because they are no longer maintained or the SQLAlchemy devs do not have the time to support them because of their low popularity.

A warning should be raised in this case.

Dialects that fall in this category:

• Firebird - It has a supported external dialect, so we should just point to sqlalchemy-firebird maintained by @pauldex
• Sybase

DBAPI modules (non exhaustive list):

• pygresql
• oursql
• pypostgresql
• adodbapi