Hibernate Query Language INSERT, UPDATE, SELECT and DELETE Example

In a previous article, we discussed HQL basics, In this article, we will learn how to create Hibernate application that performs HQL INSERT, UPDATE, SELECT, and DELETE operations.

This tutorial is upgraded to use Hibernate 6+ and Java 17.

Hibernate Query Language (HQL) is an object-oriented query language, similar to SQL, but instead of operating on tables and columns, HQL works with persistent objects and their properties. HQL queries are translated by Hibernate into conventional SQL queries, which in turn perform an action on a database.

 
HQL is extremely simple to learn and use, and the code is always self-explanatory. 

Let's briefly look at the snippets of HQL INSERT, UPDATE, SELECT, and DELETE Examples then we will develop a complete example to demonstrate the HQL CRUD example. 

1. HQL Insert Query Example

The below snippet demonstrates the usage of HQL to insert a student:

public void insertStudent() {
        Transaction transaction = null;
        try (Session session = HibernateUtil.getSessionFactory().openSession()) {
            // start a transaction
            transaction = session.beginTransaction();

            String hql = "INSERT INTO Student (firstName, lastName, email) " +
                "SELECT firstName, lastName, email FROM Student";
            Query query = session.createQuery(hql);
            int result = query.executeUpdate();
            System.out.println("Rows affected: " + result);

            // commit transaction
            transaction.commit();
        } catch (Exception e) {
            if (transaction != null) {
                transaction.rollback();
            }
            e.printStackTrace();
        }
    }

2. HQL Select Query Example

The below snippet demonstrates the usage of HQL for getting a student by id:

public Student getStudent(int id) {

        Transaction transaction = null;
        Student student = null;
        try (Session session = HibernateUtil.getSessionFactory().openSession()) {
            // start a transaction
            transaction = session.beginTransaction();

            // get an student object
            String hql = " FROM Student S WHERE S.id = :studentId";
            Query query = session.createQuery(hql);
            query.setParameter("studentId", id);
            List results = query.getResultList();

            if (results != null && !results.isEmpty()) {
                student = (Student) results.get(0);
            }
            // commit transaction
            transaction.commit();
        } catch (Exception e) {
            if (transaction != null) {
                transaction.rollback();
            }
            e.printStackTrace();
        }
        return student;
    }

The below snippet demonstrates the usage of HQL for getting all students:

    public List < Student > getStudents() {
        try (Session session = HibernateUtil.getSessionFactory().openSession()) {
            return session.createQuery("from Student", Student.class).list();
        }
    }

3. HQL Update Query Example

The below snippet demonstrates the usage of HQL to update a student's firstName where id = 1:

    public void updateStudent(Student student) {
        Transaction transaction = null;
        try (Session session = HibernateUtil.getSessionFactory().openSession()) {
            // start a transaction
            transaction = session.beginTransaction();

            // save the student object
            String hql = "UPDATE Student set firstName = :firstName " + "WHERE id = :studentId";
            Query query = session.createQuery(hql);
            query.setParameter("firstName", student.getFirstName());
            query.setParameter("studentId", 1);
            int result = query.executeUpdate();
            System.out.println("Rows affected: " + result);

            // commit transaction
            transaction.commit();
        } catch (Exception e) {
            if (transaction != null) {
                transaction.rollback();
            }
            e.printStackTrace();
        }
    }

4. HQL Delete Query Example

The below snippet demonstrates the usage of HQL to delete a student where id = 1:

public void deleteStudent(int id) {

        Transaction transaction = null;
        try (Session session = HibernateUtil.getSessionFactory().openSession()) {
            // start a transaction
            transaction = session.beginTransaction();

            // Delete a student object
            Student student = session.get(Student.class, id);
            if (student != null) {
                String hql = "DELETE FROM Student " + "WHERE id = :studentId";
                Query query = session.createQuery(hql);
                query.setParameter("studentId", id);
                int result = query.executeUpdate();
                System.out.println("Rows affected: " + result);
            }

            // commit transaction
            transaction.commit();
        } catch (Exception e) {
            if (transaction != null) {
                transaction.rollback();
            }
            e.printStackTrace();
        }
    }

Hibernate Query Language INSERT, UPDATE, SELECT, and DELETE Complete Example

Let's develop a complete example to demonstrate INSERT, UPDATE, SELECT, and DELETE HQL operations with an example.

Technologies and tools used

• Hibernate 6.1.7.Final
• IDE - Eclipse 
• Maven 3.5.3
• JavaSE 17
• MySQL - 8.0.32

Let's start developing step by step Hibernate application using Maven as a project management and build tool.

Development Steps

1. Create a Simple Maven Project
2. Project Directory Structure
3. Add jar Dependencies to pom.xml
4. Creating the JPA Entity Class(Persistent class)
5. Create a Hibernate configuration file - Java Configuration
6. Create StudentDao Class - INSERT, UPDATE, SELECT and DELETE HQL operations
7. Create the Main class and Run an Application

1. Create a Simple Maven Project

Use the How to Create a Simple Maven Project in Eclipse article to create a simple Maven project in Eclipse IDE.

2. Project Directory Structure

The project directory structure for your reference - 

3. Add jar Dependencies to pom.xml

<project
    xmlns="http://maven.apache.org/POM/4.0.0"
    xmlns:xsi="http://www.w3.org/2001/XMLSchema-instance"
 xsi:schemaLocation="http://maven.apache.org/POM/4.0.0 http://maven.apache.org/xsd/maven-4.0.0.xsd">
    <modelVersion>4.0.0</modelVersion>
    <parent>
        <groupId>net.javaguides.hibernate</groupId>
        <artifactId>hibernate-tutorial</artifactId>
        <version>0.0.1-SNAPSHOT</version>
    </parent>
    <artifactId>hibernate-hql-crud-example</artifactId>
    <properties>
        <project.build.sourceEncoding>UTF-8</project.build.sourceEncoding>
    </properties>
    <dependencies>
        <!-- https://mvnrepository.com/artifact/mysql/mysql-connector-java -->
        <dependency>
            <groupId>mysql</groupId>
            <artifactId>mysql-connector-java</artifactId>
            <version>8.0.32</version>
        </dependency>
        <!-- https://mvnrepository.com/artifact/org.hibernate/hibernate-core -->
        <dependency>
            <groupId>org.hibernate</groupId>
            <artifactId>hibernate-core</artifactId>
            <version>6.1.7.Final</version>
        </dependency>
    </dependencies>
    <build>
        <sourceDirectory>src/main/java</sourceDirectory>
        <plugins>
            <plugin>
                <artifactId>maven-compiler-plugin</artifactId>
                <version>3.5.1</version>
                <configuration>
                    <source>17</source>
                    <target>17</target>
                </configuration>
            </plugin>
        </plugins>
    </build>
</project>

4. Creating the JPA Entity Class(Persistent class)

Let's create a Student persistent class that is mapped to a database table:

package net.javaguides.hibernate.entity;

import jakarta.persistence.*;

@Entity
@Table(name = "student")
public class Student {

    @Id
    @GeneratedValue(strategy = GenerationType.IDENTITY)
    @Column(name = "id")
    private int id;

    @Column(name = "first_name")
    private String firstName;

    @Column(name = "last_name")
    private String lastName;

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

    public Student() {

    }

    public Student(String firstName, String lastName, String email) {
        this.firstName = firstName;
        this.lastName = lastName;
        this.email = email;
    }

    public int getId() {
        return id;
    }

    public void setId(int id) {
        this.id = id;
    }

    public String getFirstName() {
        return firstName;
    }

    public void setFirstName(String firstName) {
        this.firstName = firstName;
    }

    public String getLastName() {
        return lastName;
    }

    public void setLastName(String lastName) {
        this.lastName = lastName;
    }

    public String getEmail() {
        return email;
    }

    public void setEmail(String email) {
        this.email = email;
    }

    @Override
    public String toString() {
        return "Student [id=" + id + ", firstName=" + firstName + ", lastName=" + lastName + ", email=" + email + "]";
    }
}

5. Create a Hibernate configuration file - Java Configuration

The HibernateUtil Java configuration file contains information about the database and mapping file.

Let's create a HibernateUtil file and write the following code in it:

package net.javaguides.hibernate.util;

import java.util.Properties;

import org.hibernate.SessionFactory;
import org.hibernate.boot.registry.StandardServiceRegistryBuilder;
import org.hibernate.cfg.Configuration;
import org.hibernate.cfg.Environment;
import org.hibernate.service.ServiceRegistry;

import net.javaguides.hibernate.entity.Student;

public class HibernateUtil {
    private static SessionFactory sessionFactory;
    public static SessionFactory getSessionFactory() {
        if (sessionFactory == null) {
            try {
                Configuration configuration = new Configuration();

                // Hibernate settings equivalent to hibernate.cfg.xml's properties
                Properties settings = new Properties();
                settings.put(Environment.DRIVER, "com.mysql.cj.jdbc.Driver");
                settings.put(Environment.URL, "jdbc:mysql://localhost:3306/hibernate_db?useSSL=false");
                settings.put(Environment.USER, "root");
                settings.put(Environment.PASS, "root");

                settings.put(Environment.SHOW_SQL, "true");

                settings.put(Environment.CURRENT_SESSION_CONTEXT_CLASS, "thread");

                settings.put(Environment.HBM2DDL_AUTO, "create-drop");

                configuration.setProperties(settings);

                configuration.addAnnotatedClass(Student.class);

                ServiceRegistry serviceRegistry = new StandardServiceRegistryBuilder()
                    .applySettings(configuration.getProperties()).build();

                sessionFactory = configuration.buildSessionFactory(serviceRegistry);
            } catch (Exception e) {
                e.printStackTrace();
            }
        }
        return sessionFactory;
    }
}

Create StudentDao Class - INSERT, UPDATE, SELECT, and DELETE HQL operations

Let's create a separate StudentDao class and the following code to it:

package net.javaguides.hibernate.dao;

import java.util.List;

import jakarta.persistence.Query;

import org.hibernate.Session;
import org.hibernate.Transaction;

import net.javaguides.hibernate.entity.Student;
import net.javaguides.hibernate.util.HibernateUtil;

public class StudentDao {

    public void insertStudent() {
        Transaction transaction = null;
        try (Session session = HibernateUtil.getSessionFactory().openSession()) {
            // start a transaction
            transaction = session.beginTransaction();

            String hql = "INSERT INTO Student (firstName, lastName, email) " +
                "SELECT firstName, lastName, email FROM Student";
            Query query = session.createQuery(hql);
            int result = query.executeUpdate();
            System.out.println("Rows affected: " + result);

            // commit transaction
            transaction.commit();
        } catch (Exception e) {
            if (transaction != null) {
                transaction.rollback();
            }
            e.printStackTrace();
        }
    }

    public void updateStudent(Student student) {
        Transaction transaction = null;
        try (Session session = HibernateUtil.getSessionFactory().openSession()) {
            // start a transaction
            transaction = session.beginTransaction();

            // save the student object
            String hql = "UPDATE Student set firstName = :firstName " + "WHERE id = :studentId";
            Query query = session.createQuery(hql);
            query.setParameter("firstName", student.getFirstName());
            query.setParameter("studentId", 1);
            int result = query.executeUpdate();
            System.out.println("Rows affected: " + result);

            // commit transaction
            transaction.commit();
        } catch (Exception e) {
            if (transaction != null) {
                transaction.rollback();
            }
            e.printStackTrace();
        }
    }

    public void deleteStudent(int id) {

        Transaction transaction = null;
        try (Session session = HibernateUtil.getSessionFactory().openSession()) {
            // start a transaction
            transaction = session.beginTransaction();

            // Delete a student object
            Student student = session.get(Student.class, id);
            if (student != null) {
                String hql = "DELETE FROM Student " + "WHERE id = :studentId";
                Query query = session.createQuery(hql);
                query.setParameter("studentId", id);
                int result = query.executeUpdate();
                System.out.println("Rows affected: " + result);
            }

            // commit transaction
            transaction.commit();
        } catch (Exception e) {
            if (transaction != null) {
                transaction.rollback();
            }
            e.printStackTrace();
        }
    }

    public Student getStudent(int id) {

        Transaction transaction = null;
        Student student = null;
        try (Session session = HibernateUtil.getSessionFactory().openSession()) {
            // start a transaction
            transaction = session.beginTransaction();

            // get an student object
            String hql = " FROM Student S WHERE S.id = :studentId";
            Query query = session.createQuery(hql);
            query.setParameter("studentId", id);
            List results = query.getResultList();

            if (results != null && !results.isEmpty()) {
                student = (Student) results.get(0);
            }
            // commit transaction
            transaction.commit();
        } catch (Exception e) {
            if (transaction != null) {
                transaction.rollback();
            }
            e.printStackTrace();
        }
        return student;
    }

    public List < Student > getStudents() {
        try (Session session = HibernateUtil.getSessionFactory().openSession()) {
            return session.createQuery("from Student", Student.class).list();
        }
    }
}

7. Create the main App class and Run an Application

Let's test Hibernate application to connect to the MySQL database.

package net.javaguides.hibernate;

import java.util.List;

import net.javaguides.hibernate.dao.StudentDao;
import net.javaguides.hibernate.entity.Student;

public class App {
    public static void main(String[] args) {
        StudentDao studentDao = new StudentDao();
        Student student = new Student("Ramesh", "Fadatare", "rameshfadatare@javaguides.com");
        studentDao.saveStudent(student);

        studentDao.insertStudent();

        // update student
        Student student1 = new Student("Ram", "Fadatare", "rameshfadatare@javaguides.com");
        studentDao.updateStudent(student1);

        // get students
        List < Student > students = studentDao.getStudents();
        students.forEach(s - > System.out.println(s.getFirstName()));

        // get single student
        Student student2 = studentDao.getStudent(1);
        System.out.println(student2.getFirstName());

        // delete student
        studentDao.deleteStudent(1);
    }
}

Output

GitHub Repository

The complete source code of this article is available on my GitHub Repository - https://github.com/RameshMF/Hibernate-ORM-Tutorials

Conclusion

In this article, we have discussed how to create a simple Hibernate application with create HQL INSERT, UPDATE, SELECT, and DELETE operations.

You can learn more about Hibernate ORM Framework at Hibernate Tutorial

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