📌 Hibernate Tutorials

Welcome to the Hibernate Tutorials repository! 🚀 This repository contains comprehensive learning resources, code snippets, example projects, and documentation that I used while learning Hibernate.

Whether you are a beginner or an experienced developer, this repository will help you understand Hibernate ORM, its features, and how to integrate it into Java applications.

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📖 Table of Contents

• Introduction to Hibernate
• Installation & Setup
• Hibernate Core Concepts
• Mapping in Hibernate
• Working with Hibernate Annotations
• Hibernate Query Language (HQL)
• Integrating Hibernate with Spring Boot
• Performance Optimization & Caching
• Error Handling & Debugging
• Resources & References

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📌 Introduction to Hibernate

Hibernate is an ORM (Object-Relational Mapping) framework for Java that simplifies database interactions by mapping Java objects to database tables. It eliminates the need for complex SQL queries and provides a high-level abstraction for database operations.

✨ Features of Hibernate:

✔ Lightweight & Open-source
✔ Automatic ORM Mapping (No need for manual SQL queries)
✔ Supports Caching (First-Level & Second-Level Caching)
✔ Database Independence (Supports multiple databases)
✔ Annotations & XML-based Configurations
✔ Integrates with Spring & JPA

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🛠 Installation & Setup

🔹 Prerequisites:

• Java 8+ installed
• Maven or Gradle for dependency management, I used Maven fir this project.
• MySQL/PostgreSQL or any relational database, I used PostgresSQL.

🔹 Add Hibernate Dependencies (Maven)

<dependency>
    <groupId>org.hibernate</groupId>
    <artifactId>hibernate-core</artifactId>
    <version>7.x.x</version>
</dependency>

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📌 Hibernate Core Concepts

• Session & SessionFactory
• Transaction Management
• Jakarta Persistence Context
• Configuration (XML vs Annotations)

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📌 Mapping in Hibernate

• One-to-One Mapping
• One-to-Many Mapping
• Many-to-Many Mapping
• Cascade Operations

@Entity
public class Student {
    @Id
    @GeneratedValue(strategy = GenerationType.IDENTITY)
    private Long id;

    private String name;

    @OneToMany(mappedBy = "student", cascade = CascadeType.ALL)
    private List<Course> courses;
}

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📌 Working with Hibernate Annotations

• @Entity, @Table, @Id, @GeneratedValue
• @OneToOne, @OneToMany, @ManyToMany
• @Column, @Transient, @Enumerated

Example:

@Entity
@Table(name = "employees")
public class Employee {
    @Id
    @GeneratedValue(strategy = GenerationType.IDENTITY)
    private Long id;

    @Column(name = "employee_name")
    private String name;

    @Column(unique = true, nullable = false)
    private String email;
}

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📌 Hibernate Query Language (HQL)

• Basic Queries (SELECT, UPDATE, DELETE)
• Named Queries
• Pagination & Sorting

String hql = "FROM Employee WHERE salary > :salary";
Query query = session.createQuery(hql);
query.setParameter("salary", 50000);
List<Employee> employees = query.list();

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📌 Integrating Hibernate with Spring Boot

• Spring Boot + Hibernate Configuration
• Using Spring Data JPA with Hibernate
• Transaction Management with @Transactional

# application.properties
spring.datasource.url=jdbc:mysql://localhost:3306/your_db
spring.datasource.username=root
spring.datasource.password=root
spring.jpa.hibernate.ddl-auto=update
spring.jpa.show-sql=true

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📌 Performance Optimization & Caching

• First-Level & Second-Level Caching
• Batch Processing & Fetch Strategies
• Lazy vs Eager Loading

Example of Caching Configuration:

@Cacheable
@Entity
public class Product {
    @Id
    private Long id;
    private String name;
}

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📌 Error Handling & Debugging

• Common Hibernate Exceptions & Solutions
• Enabling Hibernate Logging
• SQL Injection Prevention

# Enable Hibernate SQL Logging
logging.level.org.hibernate.SQL=DEBUG
logging.level.org.hibernate.type.descriptor.sql=TRACE

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📌 Resources & References.

• Hibernate Official Documentation
• Spring Boot + Hibernate Guide
• JPA & Hibernate Best Practices
• Hibernate GitHub Repository
• Hibernate Tutorial Video by Telusko

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📢 Contributing

Want to contribute? Feel free to submit a Pull Request with new tutorials, improvements, or additional examples!

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📧 Contact

If you have any queries, feel free to reach out:
📩 Email: ganesh21renuse3@gmail.com
🌐 GitHub: GaneshRenuse

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