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)

Association cardinality


Just as relational databases define the cardinality of table relationships, ORM solutions also define the cardinality of entity associations. Before we discuss how to map associations, let's review how associations are created in a relational database. The following are the two types of relationship:

  • Foreign key relationship: You can relate a table to another by declaring a column as a foreign key of the other table. This is typically used for a 1:1 (one-to-one) or a M:1 (many-to-one) relationship. If you make the foreign key column UNIQUE, then you are defining a 1:1 relationship; otherwise, this is M:1. If you make it NULLABLE, then the relationship is optional; that is, 1:0, 1:1, M:0, or M:1.

  • Join table relationship: Another way to relate two tables is by creating a join table that will have at least two columns that store the primary keys of the rows that should be related. This is typically used for 1:M and M:N relationships. Both columns should be NON-NULLABLE...