I'm thinking of building a tool that takes an existing db and converts it into an entity relationship diagram. I was wondering if a tool like this already exists. I know that lucidchart does something like this but you can't use the output freely and programmatically, at least my understanding is that you can't.
How about this? <a href="https://github.com/BurntSushi/erd" rel="nofollow">https://github.com/BurntSushi/erd</a>