ERD Generation extension developed by Krisztian Kurucz is available in Extension Registry. It supports to generate ER Data Model from database schema. This extension is open source and hosted on Github (https://github.com/kkrisz1/staruml-reverse-db). Thanks to Krisztian.
StarUML
Sophisticated Modeling
0.0.7 – MS SQL is supported
0.1.4 – PostgreSQL is also supported
0.2.1 – MySQL is also supported