This feature is currently experimental and only lives or work with the develop branch of Bonobo. If you like to live on the edge, you can already test it, but expect the setup to be a lot more painful and manual than the usual mainline (master branch) features.
Bonobo-SQLAlchemy is a lightweight bridgepackage that adds SQL databases related capabilities to Bonobo.
To use it, you need to have both the develop branch of bonobo installed in your current python environment, and the bonobo-sqlalchemy package installed.
As the extension is currently in early preview stage, expect things not to go smooth.
If you're ready for it, go ahead and read the documentation.