background preloader

Hibernate

Facebook Twitter

Hibernate Performance Tuning. Hibernate is a powerful, high performance object/relational persistence and query service. Hibernate lets you develop persistent classes following object-oriented idiom - including association, inheritance, polymorphism, composition, and collections. Hibernate allows you to express queries in its own portable SQL extension (HQL), as well as in native SQL, or with an object-oriented Criteria and Example API. Quintessential to using any ORM framework like hibernate is to know how to leverage the various performance tuning methods supported by the framework. In this volume Wings Jiang discusses three performance tuning strategies for hibernate: SQL OptimizationSession ManagementData Caching SQL Optimization When using Hibernate in your application, you already have been coding HQL (Hibernate Query Language) somewhere.

Session Management Undoubtedly, Session is the pith of Hibernate. Data Caching Using cache based on SessionFactory level (Application layer level cache). 1. 2. 3. 5. 6. 7. 01. 02. 10. Java - Hibernate show real SQL. Spring 3 and Annotation Based Hibernate 4 Example. Spring 3 and Annotation Based Hibernate 4 Example, uses MySQL database to store the user data. Database Table Here's database table used in example. Hibernate Context file Hibernate Context file configures hibernate for your application and is loaded during spring startup, it creates DataSource, SessionFactory, TransactionManager and defines <tx:annotation-driven /> element that switches on the transactional behavior in presence of @Transactional annotations on the Service or Dao classes. org.springframework.jdbc.datasource.DriverManagerDataSource, dataSource, you can specify your database connection settings. org.springframework.orm.hibernate4.LocalSessionFactoryBean, sessionFactory, takes the dataSource, hibernate mapping location and hibernate settings. org.springframework.orm.hibernate4.HibernateTransactionManager, transactionManager, takes sessionFactory, which is then provides to <tx:annotation-driven /> element.

Servlet Context File Entity Class Data Access Object (Dao) User Service. Java Persistence/Tables. A typical mapping of a persist class will map the class to a single table. In JPA this is defined through the @Table annotation or <table> XML element. If no table annotation is present, the JPA implementation will auto assign a table for the class. The JPA default table name is the name of the class (minus the package) with the first letter capitalized. Each attribute of the class will be stored in a column in the table. Example mapping annotations for an entity with a single table[edit] ... Example mapping XML for an entity with a single table[edit] Although in the ideal case each class would map to a single table, this is not always possible.

These are all advanced cases, some are handled by the JPA Spec and many are not. Multiple tables[edit] Sometimes a class maps to multiple tables. JPA allows multiple tables to be assigned to a single class. In a multiple table entity, each mapping must define which table the mapping's columns are from. ... Multiple tables with foreign keys[edit] Java - JPA primary key auto generate. Introduction to Hibernate framework. Hibernate Architecture tutorial.

Hibernate was started in 2001 by Gavin King as an alternative to using EJB2-style entity beans. Its mission back then was to simply offer better persistence capabilities than offered by EJB2 by simplifying the complexities and allowing for missing features. Early in 2003, the Hibernate development team began Hibernate2 releases which offered many significant improvements over the first release. JBoss, Inc. (now part of Red Hat) later hired the lead Hibernate developers and worked with them in supporting Hibernate. Hibernate is part of JBoss (a division of Red Hat) Enterprise Middleware System (JEMS) suite of products. 1. Hibernate is an Object-relational mapping (ORM) tool. A “virtual object database” is created that can be used from within the programming language. Hibernate is a persistence framework which is used to persist data from Java environment to database. 2. The above diagram shows minimal architecture of Hibernate. 2.1 SessionFactory (org.hibernate.SessionFactory) 3.

<? 4. 5. Hibernate Maven MySQL hello world example (XML Mapping) In this tutorial, we will try to write a small hello world program using Hibernate, MySQL and Maven. We will create a Java project using Maven and will then try to add Hibernate on it. Following are the tools and technologies used in this project. Java JDK 5 or aboveEclipse IDE 3.2 or aboveMaven 3.0 or aboveHibernate 3.0 or aboveMySQL 5.0 or above 1.

Database Creation For this tutorial, we will create a simple table “employe” in MySQL. Thus, following will be the connection string to connect with MySQL. 2. Open a command prompt and execute following code to generate a Maven Java project. Once you execute above command, a project “HibernateHelloWorldXML” is created. Once this is done, we will convert it to be compatible with Eclipse. 3. Open Eclipse and import the above Java project. Once imported, the folder structure will look like following: Important: In case you get following error after importing project in Eclipse: 4.

Add following dependencies to Maven pom.xml. 5. 6. 7. 8. 9. Hibernate - JPA Annotations. Hibernate One To Many Annotation tutorial with example. Hibernate annotations. Welcome to the Hibernate Tutorial Series. In previous tutorial we saw how to implement One to Many relationship using XML mapping. In this tutorial we will modify the source code from previous One To Many XML mapping tutorial and add JPA/Annotation support to it. 1. Database Setup For this example, we will use MySQL database. 2. Download the source code: Hibernate-one-to-many-set-example.zip (9 KB) and import the project in Eclipse. 3.

File: pom.xml <? 3. We are not going to use hibernate mapping files or hbm files as we will map the model using Java 5 Annotations. 4. File: Employee.java @ManyToOne annotation defines a single-valued association to another entity class that has many-to-one multiplicity. @JoinColumn is used to specify a mapped column for joining an entity association. File: Department.java @OneToMany annotation defines a many-valued association with one-to-many multiplicity. The association may be bidirectional. 5. File: hibernate.cfg.xml <? 6. 7. Output: 8. Download Source Code.