If you need to build complex SQL databases you will find DbDesigner quite a useful tool. It allows you to construct your DB in an intuitive and easy to use environment, where you have a visual representation of the tables and relations contained in your project. You can quickly see the fields in a table or how each table relates to the others. After you are finished, DbDesigner can export the schema of the database into an .sql script, or directly connect to a database backend and build it there.