This is basically the idea behind [Thin Backend](https://thin.dev/). Instead of exposing raw SQL strings we have a few high level functions to compose queries in a nice way and to do all kind of CRUD operations. These functions map 1:1 to SQL.

We use a WebSocket connection to keep all queries fast. Auth is solved with row level security.

It's even in the name: The backend layer is just a "thin" layer over the database. Most of the business logic is then implemented in a "rich" client/frontend.