Hibernate - Creating Data Access Objects (DAOs)

How to Program with Java Podcast

Data Access Objects – What are they?

Data Access Objects (or DAOs for short) are used as a direct line of connection and communication with our database. DAOs are used when the actual CRUD (CRUD = Create, Read, Update, Delete) operations are needed and invoked in our Java code. These data access objects also represent the “data layer” of our application.

These objects are still just plain old Java objects that incorporate the use of some Hibernate annotations to give them the functionality we need from them. Again, that functionality being the communication with the database.

Also, believe it or not, the concept of creating a file specifically for accessing the database is a design pattern. It’s called the Data Access Object Pattern and you can read more about it from this nice short Wiki article.

What Hibernate Annotations Should We Use?

Okay, so now that you’re somewhat familiar with DAOs, it’s time to learn how to integrate these plain old Java objects with our Hibernate framework (so they actually do the work we need them to do).

There are two main annotations that you need to be familiar with:

• @Repository
• @Transactional

To learn more, visit our show notes page via http://howtoprogramwithjava.com/session52