Redis and RDBMS coexistence (hopefully cooperation) in Flask applications
You should have no problem using an ORM because, in the end, it just stores strings, numbers and other values. So you could have a game in progress, and keep its state in Redis, including the players' IDs from the SQL player table, because the ID is just a unique integer.
I'm developing a multi-player game in Python with a Flask frontend, and I'm using it as an opportunity to learn more about the NoSQL way of doing things.
Redis seems to be a good fit for some of the things I need for this app, including storage of server-side sessions and other transient data, e.g. what games are in progress, who's online, etc. There are also several good Flask/Redis recipes that have made things very easy so far.
However, there are still some things in the data model that I would prefer lived inside a traditional RDBMS, including user accounts, logs of completed games, etc.  It's not that Redis can't do these things, but I just think the RDBMS is more suited to them, and since Redis wants everything in memory, it seems to make sense to "warehouse" some of this data on disk.
The one thing I don't quite have a good strategy for is how to make these two data stores live happily together.  Using ORMs like SQLAlchemy and/or redisco seems right out, because the ORMs are going to want to own all the data that's part of their data model, and there are inevitably times I'm going to need to have classes from one ORM know about classes from the other one (e.g. "users are in the RDBMS, but games are in Redis, and games have users participating in them.)
Does anyone have any experience deploying python  web apps using a NoSQL store like Redis for some things and an RDBMS for others?  If so, do you have any strategies for making them work together?