Hibernate is an open-source ORM (Object-Relational Mapping) framework for Java. It simplifies database operations by mapping Java objects to database tables. Instead of writing complex SQL queries, Hibernate handles database interactions and allows developers to work with Java objects directly.
Importance of Hibernate
- Simplifies Database Operations: Hibernate abstracts away complex SQL, making it easier to work with relational data.
- Portability: Hibernate works with many relational databases, making your application database-agnostic.
- Automatic Table Generation: It can automatically generate database tables based on your Java class structure.
Features of Hibernate
- Mapping Java Objects to Database Tables: Each Java object (entity) corresponds to a table in the database.
- Session Management: Hibernate provides a
Sessionobject to manage database transactions, queries, and CRUD operations. - Automatic Data Persistence: Hibernate automatically saves changes made to Java objects to the database.
Hibernate Architecture Overview
- SessionFactory: Creates
Sessionobjects. It is a heavyweight object used to configure Hibernate. - Session: Provides methods for CRUD operations and querying the database.
- Transaction: Manages database transactions, ensuring data consistency and rollback capabilities.
- Configuration: Contains Hibernate configuration settings (e.g., database connection details, dialect).
Example Code
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// Step 1: Configure Hibernate SessionFactory factory = new Configuration() .configure("hibernate.cfg.xml") .addAnnotatedClass(Student.class) .buildSessionFactory(); // Step 2: Open a Session Session session = factory.getCurrentSession(); // Step 3: Create a new Student object Student tempStudent = new Student("John", "Doe", "john.doe@example.com"); // Step 4: Start a transaction session.beginTransaction(); // Step 5: Save the student object session.save(tempStudent); // Step 6: Commit the transaction session.getTransaction().commit(); // Step 7: Close the factory factory.close(); |
In this example,
- The
SessionFactoryis responsible for creating sessions. - A
Studentobject is saved to the database, and Hibernate takes care of the underlying SQL.
