Last week I gave a database training in Switzerland. We had a look into relational databases, normalization theory, some good principles on database modelling, SQL language.
As of the used tools, we had an overview of Oracle 11g free database server, as well as Oracle SQL Developer tool to access the database systems. The E/R diagram toolkit we used to train on was TOAD data modeller. The previous versions of the tool were freeware, but the last implementations available are only evaluation for 2 weeks. You could try to find an old version that does the general work - database drawing, generation of SQL (as well as simple reverse engineering), creation of relations - identifying and non-identifying, as for one-to-one, one-to-many and many-to-many relationships.
In my training here I also extend the presentations with PL/SQL tips and tricks, Object relational mapping with Hibernate and JPA and few practical projects in classes.