Is there any available tool/script to visualize an Erlang Mnesia schema?
Ideally it should generate .dot files to be read with Graphviz or any other similar piece of software.
Short answer: I haven't heard of anything available.
What would you visualize about the schema? It would be hard to generate a visualization of the relationships between tables because there's no explicit data stored about that. (No schema I've encountered actually uses mnesia's (exotic) foreign_key functionality.)
I can imagine some visualization of the replication layout of the schema (which nodes have which fragments of which copies of which tables), but due to the lack of table inter-relationship information, I don't think there are visualizations available for that.