May 2008
Intermediate to advanced
276 pages
5h 23m
English
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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 ...
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O’Reilly covers everything we've got, with content to help us build a world-class technology community, upgrade the capabilities and competencies of our teams, and improve overall team performance as well as their engagement.Julian F.
I wanted to learn C and C++, but it didn't click for me until I picked up an O'Reilly book. When I went on the O’Reilly platform, I was astonished to find all the books there, plus live events and sandboxes so you could play around with the technology.Addison B.
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I'm always learning. So when I got on to O'Reilly, I was like a kid in a candy store. There are playlists. There are answers. There's on-demand training. It's worth its weight in gold, in terms of what it allows me to do.