There are a few database systems that are a bit different. They are libraries that can be linked directly to your application. Linking can be done statically (during the compilation/linking step) or dynamically (using a shared library or DLL). Here I want to show two cases:
- SQLite [1] used from R on data frames
- DuckDB [2] used from Python, again on data frames
So these databases don't only run inside R or Python but also can operate directly on data frames.
