Book Image

Mastering Hibernate

By : Ramin Rad, Koushik Srinivas Kothagal
Book Image

Mastering Hibernate

By: Ramin Rad, Koushik Srinivas Kothagal

Overview of this book

Hibernate has been so successful since its inception that it even influenced the Java Enterprise Edition specification in that the Java Persistence API was dramatically changed to do it the Hibernate way. Hibernate is the tool that solves the complex problem of Object Relational Mapping. It can be used in both Java Enterprise applications as well as .Net applications. Additionally, it can be used for both SQL and NoSQL data stores. Some developers learn the basics of Hibernate and hit the ground quickly. But when demands go beyond the basics, they take a reactive approach instead of learning the fundamentals and core concepts. However, the secret to success for any good developer is knowing and understanding the tools at your disposal. It’s time to learn about your tool to use it better This book first explores the internals of Hibernate by discussing what occurs inside a Hibernate session and how Entities are managed. Then, we cover core topics such as mapping, querying, caching, and we demonstrate how to use a wide range of very useful annotations. Additionally, you will learn how to create event listeners or interceptors utilizing the improved architecture in the latest version of Hibernate.
Table of Contents (16 chapters)

Criteria objects


Another way to create a fetch query is using criteria objects. This is more in tune with the object-oriented mindset. However, the real advantage that this brings is that this makes composing dynamic queries easier.

Criteria queries are composed from an object graph, and as new search criteria are added, new objects (Restrictions, Order, and so on) are added to the graph. This is especially very useful when you are building a report or search screen in your application, for example, navigating through items in an online store.

In its simplest form, a Criteria object is created, as follows:

Criteria criteria = session.createCriteria(Person.class);
List<Person> persons = criteria.list();

In this case, the Person entity is configured to fetch the associated entities eagerly, and the criteria API follows this instruction.

You can further modify the Criteria object, for example, by adding a WHERE clause:

List<Person> persons = criteria
  .add(Restrictions.eq("lastname"...