Prior knowledge or experience in database programming (SQL, JDBC, ORM, JPA, etc.) is not required, but some background in using the Java language is essential.
Can I use ObjectDB to access a relational database?
To access relational databases using the Java Persistence API (JPA) you will need an Object Relational Mapping (ORM) tool, such as Hibernate, TopLink, EclipseLink, Open JPA or DataNucleus. The DataNucleus ORM implementation supports also the Java Data Objects (JDO) API. ObjectDB is a full featured standalone Object Database Management System (ODBMS) and not an ORM tool, so it is not intended and cannot be used to access other database management systems.