Search icon CANCEL
Subscription
0
Cart icon
Your Cart (0 item)
Close icon
You have no products in your basket yet
Save more on your purchases now! discount-offer-chevron-icon
Savings automatically calculated. No voucher code required.
Arrow left icon
Explore Products
Best Sellers
New Releases
Books
Videos
Audiobooks
Learning Hub
Conferences
Free Learning
Arrow right icon
Arrow up icon
GO TO TOP
Developing Middleware in Java EE 8

You're reading from   Developing Middleware in Java EE 8 Build robust middleware solutions using the latest technologies and trends

Arrow left icon
Product type Paperback
Published in Jun 2018
Publisher Packt
ISBN-13 9781788391078
Length 252 pages
Edition 1st Edition
Languages
Tools
Concepts
Arrow right icon
Author (1):
Arrow left icon
Abdalla Mahmoud Abdalla Mahmoud
Author Profile Icon Abdalla Mahmoud
Abdalla Mahmoud
Arrow right icon
View More author details
Toc

Table of Contents (12) Chapters Close

Preface 1. Delving into Java EE 8 FREE CHAPTER 2. Dependency Injection Using CDI 2.0 3. Accessing the Database with JPA 2.1 4. Validating Data with Bean Validation 2.0 5. Exposing Web Services with JAX-RS 2.1 6. Manipulating JSON with JSON-B 1.0 7. Communicating with Different Systems with JMS 2.0 8. Sending Mails with JavaMail 1.6 9. Securing an Application with Java Security 1.0 10. Making Interactive Applications with WebSockets 1.1 11. Other Books You May Enjoy

Performing CRUD operations


In the following sections, we are going to learn how to use JPA for performing the four basic data access operations: creating, retrieving, updating, and deleting entities.

Managed versus detached entities

One of the most important concepts to understand about the JPA framework is that every entity has a state at each point during runtime. An entity can be in one of two states:

  • Managed: A managed entity is one that is synchronized with the database; any changes in the entity state will be reflected in the database. In other words, the persistence provider is tracking a managed entity state, and keeps updating the database with any changes that occur to its state.
  • Detached: A detached entity is one that is not synchronized with the database; any changes in the entity state will not be reflected to the database. The persistence provider does not track any changes that occur to the entity.

As you will see later, by performing the different CRUD operations supported by...

lock icon The rest of the chapter is locked
Register for a free Packt account to unlock a world of extra content!
A free Packt account unlocks extra newsletters, articles, discounted offers, and much more. Start advancing your knowledge today.
Unlock this book and the full library FREE for 7 days
Get unlimited access to 7000+ expert-authored eBooks and videos courses covering every tech area you can think of
Renews at €18.99/month. Cancel anytime