EJB 3.0 supports a field-based relational model: each Java field represents a database column. The tutorial shows the configuration, classes, and client code for a single-table entity.

Transaction annotations make reliable database updates clear, straightforward and scalable. Transaction boundaries protect database consistency by enforcing an all-or-none policy and using the database's locking capabilities for scalability.

Basic CMP example showing configuration, classes, and client code for a single-table bean.

Describes the basic create/remove api for entity beans.

Demonstrates protecting database updates using some basic transaction patterns.

The EJB 3.0 Query API resembles the JDBC PreparedStatement with enhanced SQL and direct support for objects.0.

The Many-to-One link is the foundation of persistent relations. It links a source table to a destination with a database REFERENCES column. Many-to-One adds two capabilities: SQL extensions for links and direct lookup of target beans through field references.

The @OneToMany relation adds collection extensions to the query language and provides a Java Collection containing the children. @OneToMany represents a collection of children belonging to a parent, like students in Gryffindor house at Hogwarts school.

Illustrates using many-to-many relations of EJB 3.0.

EJB 3.0 supports database-backed inheritance, allowing for persistent-backed polymorphism and more sophisticated object-oriented modelling.

Stateless sessions make database queries and updates robust by setting transaction boundaries at each business method. This stateless session bean example annotates a single business method with a SUPPORTS transaction attribute, marking the method as a read-only transaction boundary.