Mapping Relationships with Hibernate
In the past we have learned about database relationships, specifically the One-to-Many as well as the Many-to-Many and One-to-One and that was all good, great and grand… But now I want to talk about how to create those same relationships inside of Hibernate. Specifically, I want to focus on the One-to-Many relationship in Hibernate and how we go about mapping it out in our Java objects. But before we do, a word on unidirectional and bidirectional relationships. Unidirectional vs Bidirectional In Hibernate, it’s possible to map all three relationships that are available in a standard database, these include: One-to-One One-to-Many Many-to-Many But what Hibernate also includes is the ability to make EACH of those relationships either unidirectional or bidirectional. This means that we can have a unidirectional One-to-One and a bidirectional One-to-One mapping, as well as a unidirectional One-to-Many and a bidirectional One-to-Many, as well as a unidirectional Many-to-Many and a bidirectional Many-to-Many relationship. That’s a lot of relationships! So what exactly are unidirectional and bidirectional relationships? Learn more on the show notes page via http://howtoprogramwithjava.com/session53