Honestly I think the reason it is “extremely basic” is because while it has been trained on “the entire internet” it doesn’t know anything about your specific database schema beyond what you provided in your prompts.
If these LLMs were cheap and easy to train (or is it fine tune?) using your own schema and code base on top of its existing “whole internet” training data… it could almost certainly do more than just provide “basic stuff”.
Of course I think the training for your own personal stuff would need to be “different” somehow so it knows that while most of its training is generalistic the stuff you feed it is special and it needs to apply the generalist training as a means for understanding your personal stuff.
Or something like that. Whatever the case is it would need to be cheap, quick and easy to pick up a generalist LLM and supplement it with the entirety of your own personal corpus.
For many cases this is more than enough to solve some hard problems well enough.