I'm interested to build something like this too. Would you open source it so we can collaborate? It's surprising how few OSS alternatives exist for low-code programming.
Webase uses MongoDB for the dynamic data layer so currently we aren't using SQL or allowing direct queries. We may add that in the future if there is demand, but to start we are focused on non-SQL type users.
The latest iteration of the treehouse includes rails that make it much much safer for children!!