I would change two things:

First, I would (try to) make the tables parameter optional, defaulting to all tables in the current schema. This is obviously not possible for CSV or some of the other file-based DBDs though.

Second, I'm not sure I like the neccessity of spelling out the whole CREATE TABLE statement when the function call is named create_table as well. Maybe just calling that function do would make me feel better, as changing the SQL string is impossible for CREATE TEMP TABLE...

You could guess the relations between tables from columns with the same name. But then again, that might be too much magic in one place ...