Sign In Start Free Trial
Account

Add to playlist

Create a Playlist

Modal Close icon
You need to login to use this feature.
  • Book Overview & Buying EJB 3 Developer Guide
  • Table Of Contents Toc
  • Feedback & Rating feedback
EJB 3 Developer Guide

EJB 3 Developer Guide

By : Michael Sikora
4.2 (6)
close
close
EJB 3 Developer Guide

EJB 3 Developer Guide

4.2 (6)
By: Michael Sikora

Overview of this book

Table of Contents (18 chapters)
close
close
EJB 3 Developer Guide
Credits
About the Author
About the Reviewers
Preface
1
Annotations and Their Corresponding Packages

Chapter 5. The Java Persistence Query Language

EJB 3 provides the Java Persistence Query Language (JPQL). In this chapter we will cover:

  • Projections

  • GROUP BY and HAVING clauses

  • Joins

  • Subqueries

  • Dynamic Queries

  • Functions

  • Queries with parameters

  • Handling Date and Time

  • Bulk update and delete operations

  • Native SQL

Introduction

A rather limited query language, EJB QL, was provided in EJB 2.0 and 2.1. JPQL enhances EJB QL by providing the following features: JOINs, GROUP BY, HAVING, projection, subqueries, dynamic queries, bulk update and delete. We shall see examples of all these features in this chapter.

JPQL is similar to the SQL language for querying relational databases. However, JPQL queries are expressed in Java objects rather than tables and columns. As SQL dialects differ between relational database vendors, JPQL has an added advantage of portability across databases. The entity manager uses the JDBC configuration specified in the persistence.xml file to convert the JPQL query to native SQL.

There...

Visually different images
CONTINUE READING
83
Tech Concepts
36
Programming languages
73
Tech Tools
Icon Unlimited access to the largest independent learning library in tech of over 8,000 expert-authored tech books and videos.
Icon Innovative learning tools, including AI book assistants, code context explainers, and text-to-speech.
Icon 50+ new titles added per month and exclusive early access to books as they are being written.
EJB 3 Developer Guide
notes
bookmark Notes and Bookmarks search Search in title playlist Add to playlist font-size Font size

Change the font size

margin-width Margin width

Change margin width

day-mode Day/Sepia/Night Modes

Change background colour

Close icon Search
Country selected

Close icon Your notes and bookmarks

Confirmation

Modal Close icon
claim successful

Buy this book with your credits?

Modal Close icon
Are you sure you want to buy this book with one of your credits?
Close
YES, BUY

Submit Your Feedback

Modal Close icon
Modal Close icon
Modal Close icon