In this tutorial, we are going to learn about Hibernate Native SQL with example. Hibernate gives a facility to execute SQL commands directly on the database with a technique called native SQL.

To execute SQL commands from hibernate, Hibernate given us SQLQuery. SQLQuery is an interface which is coming from the org.hibernate package.

We can obtain the SQLQuery instance by calling the createSQLQuery() on hibernate session like below :

Hibernate Native SQL for Complete Row :

String qry = "select * from student";
SQLQuery sqlQuery = session.createSQLQuery(qry);

In the above example, we try to select the entire row with the SQL command. In this case, Hibernate converts each row into Object[] but not into Object of POJO class.

If we want to tell the Hibernate, that convert each row into an object of POJO class, we need to call addEntity() method of SQLQuery object. That Query object is called an EntityQuery.

String qry = "select * from student";
SQLQuery sqlQuery = session.createSQLQuery(qry);

sqlQuery.addEntity(Student.class);

List list = sqlQuery.list();

In the above example, now the list contains Student class objects. So that we can directly cast into Student type :

Iterator iterator = list.iterator();
        while (iterator.hasNext()) {
            Student student = (Student) iterator.next();
            System.out.println("sId : " + student.getStudentId() + " sName : "
                    + student.getStudentName() + " age : " + student.getAge());

Hibernate Native SQL for Partial Row :

While reading partial row with native SQL query, to find the column types, hibernate internally uses ResultSetMetaData. If we want to tell to hibernate explicitly about the columns, which we want to select, then we can call addScalar() on SQLQuery object like below :

String qry = "select * from student";
SQLQuery sqlQuery = session.createSQLQuery(qry);

sqlQuery.addScalar("sid", IntegerType.INSTANCE);
sqlQuery.addScalar("sname", StringType.INSTANCE);

List list = sqlQuery.list();

In the above example, we pass the two parameters to addScalar() method1 is for the column name, and 2nd is the type of column. In this case, the list contains Object[], since it is a partial entity. Why?

Likewise, we can do even non-select operations like insert, update and delete with Hibernate Native SQL query. Here is the complete example :

Hibernate Native SQL Complete Example :

Creating Student Pojo

Student.java

package com.otp.hibernate.pojo;

public class Student {
    private int studentId;
    private String studentName;
    private String address;
    private int age;

    public int getStudentId() {
        return studentId;
    }

    public void setStudentId(int studentId) {
        this.studentId = studentId;
    }

    public String getStudentName() {
        return studentName;
    }

    public void setStudentName(String studentName) {
        this.studentName = studentName;
    }

    public String getAddress() {
        return address;
    }

    public void setAddress(String address) {
        this.address = address;
    }

    public int getAge() {
        return age;
    }

    public void setAge(int age) {
        this.age = age;
    }
}

Hibernate Mapping class :

<?xml version="1.0" encoding="UTF-8"?>
<!DOCTYPE hibernate-mapping PUBLIC
  "-//Hibernate/Hibernate Mapping DTD 3.0//EN"
  "http://hibernate.sourceforge.net/hibernate-mapping-3.0.dtd">
<hibernate-mapping>
    <class name="com.otp.hibernate.pojo.Student" table="student"
        schema="onlinetutorialspoint">
        <id name="studentId" column="sid">
            <generator class="increment" />
        </id>
        <property name="studentName" column="sname" />
        <property name="address" column="address" />
        <property name="age" column="age" />
    </class>
</hibernate-mapping>

Run the application:

Main.java

import java.util.Iterator;
import java.util.List;

import org.hibernate.Filter;
import org.hibernate.Hibernate;
import org.hibernate.Query;
import org.hibernate.SQLQuery;
import org.hibernate.Session;
import org.hibernate.SessionFactory;
import org.hibernate.Transaction;
import org.hibernate.boot.registry.StandardServiceRegistryBuilder;
import org.hibernate.cfg.Configuration;
import org.hibernate.type.IntegerType;
import org.hibernate.type.StringType;

import com.otp.hibernate.pojo.Student;

public class Main {

    public static void main(String[] args) {
        Configuration configuration = new Configuration()
                .configure("hibernate.cfg.xml");
        StandardServiceRegistryBuilder builder = new StandardServiceRegistryBuilder()
                .applySettings(configuration.getProperties());
        SessionFactory factory = configuration.buildSessionFactory(builder
                .build());

        Session session = factory.openSession();
        String qry = "select * from student";
        SQLQuery sqlQuery = session.createSQLQuery(qry);

        List list = sqlQuery.list();

        Iterator iterator = list.iterator();

        while (iterator.hasNext()) {
            Object[] object = (Object[]) iterator.next();
            System.out.println("sId : " + object[0] + " sName : " + object[1]
                    + " age : " + object[2]);
        }

        // addEntity
        System.out.println("***********Entity*************");
        String qry2 = "select * from student";
        SQLQuery sqlQuery2 = session.createSQLQuery(qry2);
        sqlQuery2.addEntity(Student.class);

        List list2 = sqlQuery2.list();
        Iterator iterator2 = list2.iterator();

        while (iterator2.hasNext()) {
            Student student = (Student) iterator2.next();
            System.out.println("sId : " + student.getStudentId() + " sName : "
                    + student.getStudentName() + " age : " + student.getAge());
        }

        // addSclar
        System.out.println("***********SCALAR*************");

        String qry3 = "select * from student";
        SQLQuery sqlQuery3 = session.createSQLQuery(qry3);

        sqlQuery3.addScalar("sid", IntegerType.INSTANCE);
        sqlQuery3.addScalar("sname", StringType.INSTANCE);

        List list3 = sqlQuery3.list();
        Iterator iterator3 = list3.iterator();

        while (iterator3.hasNext()) {
            Object[] object = (Object[]) iterator3.next();
            System.out.println("sId : " + object[0] + " sName : " + object[1]);
        }

        // update
        System.out.println("**********Update**********");

        Transaction transaction = session.beginTransaction();
        String qry4 = "update student set age=:age where sid=:id";
        SQLQuery sqlQuery4 = session.createSQLQuery(qry4);
        sqlQuery4.setParameter("id", 2);
        sqlQuery4.setParameter("age", 30);
        sqlQuery4.executeUpdate();

        transaction.commit();
        System.out.println("Completed");
        session.clear();
        session.close();
    }
}

Output:

sId : 1 sName : vizag age : 20
sId : 2 sName : vizag age : 40
sId : 3 sName : hyderabad age : 30
***********Entity*************
sId : 1 sName : chandra age : 20
sId : 2 sName : shekhar age : 40
sId : 3 sName : rahul age : 30
***********SCALAR*************
sId : 1 sName : chandra
sId : 2 sName : shekhar
sId : 3 sName : rahul
**********Update**********
Completed

Though we have a facility to execute SQL commands in hibernate app, it is not recommended because it kills one of the main advantages of hibernate, That is our application becomes database dependent.

The complete example is available for download, have a look.

Happy Learning 🙂