9.4. Entity Beans and JDO

Having discussed session and message-driven enterprise beans above, let's now turn to another type of enterprise bean, entity beans. As per the EJB specification[4] , an entity enterprise bean has the following characteristics:

[4] http://java.sun.com/products/ejb/

  • Provides an object view of data in the database.

  • Allows shared access from multiple users.

  • Can be long-lived (lives as long as the data in the database).

Two different types of entity beans exist: container-managed persistence (CMP) and bean-managed persistence (BMP) entity beans. Both types of entity beans can be created and removed, and queried with a language named EJBQL. They also have an identity, their primary key. Does this all seem remarkably similar ...

Get Core Java™ Data Objects now with the O’Reilly learning platform.

O’Reilly members experience books, live events, courses curated by job role, and more from O’Reilly and nearly 200 top publishers.

Start your free trial