Expanding on the previous subject about the generation of a back-end and rest API from existing database .
- Netbeans has a generate entities from database script
- Jeddict . This could be already be pre-installed in some Netbeans products
- Dali persistence tools from Eclipse
- Hibernate Tools
Jipster offers the on line tool JDL-studio: there you can visually create tables and relationships. Entities generation from database is only available with an external tool. Beware of some cumbersome issues.
Last and most important: your good SQL database may be able to generate the text of the most important queries towards you database. Look at PostgreSql . Their pgAdmin toll has many features like these for generating things.