Book Image

Java Hibernate Cookbook

Book Image

Java Hibernate Cookbook

Overview of this book

This book will provide a useful hands-on guide to Hibernate to accomplish the development of a real-time Hibernate application. We will start with the basics of Hibernate, which include setting up Hibernate – the pre-requisites and multiple ways of configuring Hibernate using Java. We will then dive deep into the fundamentals of Hibernate such as SessionFactory, session, criteria, working with objects and criteria. This will help a developer have a better understanding of how Hibernate works and what needs to be done to run a Hibernate application. Moving on, we will learn how to work with annotations, associations and collections. In the final chapters, we will see explore querying, advanced Hibernate concepts and integration with other frameworks.
Table of Contents (15 chapters)
Java Hibernate Cookbook
Credits
About the Authors
About the Reviewers
www.PacktPub.com
Preface
Index

Using formula in hibernate


Sometimes, we need a calculated column in hibernate; at such a time, the formula feature is used. For this, we will use the @Formula annotation with the field.

The field annotated with the @Formula annotation is a read-only field, and the formula is only applied while using the SELECT operation.

How to do it…

To show how formula works, we will change a Product class and add a field, capitalName, which has no physical column in the product table, as shown in the following code:

Source file: Product.java

@Entity
@Table(name = "product")
public class Product {

  @Id
  @GeneratedValue
  @Column(name = "id")
  private long id;

  @Column(name = "name")
  private String name;

  @Formula("UPPER(name)")
  private String capitalName;
  
  @Column(name = "price")
  private double price;

  @ManyToOne
  @JoinColumn(name = "category_id")
  private Category category;

  // Getters and setters
}

Now, we will run a code to show how it works:

Code

Criteria criteria = session.createCriteria...