Table Per Hierarchy – Hibernate

Table Per Hierarchy – Hibernate
Table per class hierarchy is mapping all values in one table. The code given below is tested in NetBeans.

1) In Netbeans file–>new project –>java –>java webapplication
2) Give webapplication a name(“TPH”) –> Next
3) Select Hibernate Framework and choose the database where you want to create this table

Create 3 java files,
Student.java
Regular.java
Parttime.java

Create a folder named “pojo” inside source packages
Student.java

public class Student {
    
    String sname;
    String sdept;
    int id;

    public String getSname() {
        return sname;
    }

    public void setSname(String sname) {
        this.sname = sname;
    }

    public String getSdept() {
        return sdept;
    }

    public void setSdept(String sdept) {
        this.sdept = sdept;
    }

    public int getId() {
        return id;
    }

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

Regular.java

public class Regular extends Student {
    
    private String regularfees;

    public String getRegularfees() {
        return regularfees;
    }

    public void setRegularfees(String regularfees) {
        this.regularfees = regularfees;
    }
    
}

Parttime.java

public class Parttime extends Student {
    
    private String partimefees;

    public String getPartimefees() {
        return partimefees;
    }

    public void setPartimefees(String partimefees) {
        this.partimefees = partimefees;
    }
    
}

hibernate.cfg.xml

<hibernate-configuration>
  <session-factory>
     <property name="hibernate.hbm2ddl.auto">update</property> //update -->Checks if table exists, if table exists values get updated or new table will get created
    <property name="hibernate.dialect">org.hibernate.dialect.MySQLDialect</property>
    <property name="hibernate.connection.driver_class">com.mysql.jdbc.Driver</property>
    <property name="hibernate.connection.url">"url"</property>
    <property name="hibernate.connection.username">"username"</property>
    <property name="hibernate.connection.password">"password"</property>
    <mapping resource="student.hbm.xml"/>
  </session-factory>
</hibernate-configuration>

Right Click –> New–> Hibernate Mapping Wizard –>student.hbm.xml

<?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="pojo.Student" table="student" discriminator-value="stud">
        <id name="id" type="int">
            <column name="id"/>
            <generator class="increment"></generator>
        </id>
        <discriminator column="type" type="string"></discriminator> 
        <property name="sname" type="string">
            <column name="Name"/>
        </property>
        <property name="sdept" type="string">
            <column name="Department"/>
        </property>
        
        <subclass name="pojo.Regular" discriminator-value="Regular">
            <property name="regularfees" type="string">
            <column name="regularfees"/>
            </property> 
        </subclass>
        
         <subclass name="pojo.Parttime" discriminator-value="pt">
            <property name="partimefees" type="string">
            <column name="partimefees"/>
            </property> 
        </subclass>
    </class>
</hibernate-mapping>

Inside pojo create a javaclass
Save.java

public class Save {
    public static void main(String args[])
    {
        Transaction trans=null;
        Session session=new Configuration().configure("hibernate.cfg.xml").buildSessionFactory().openSession(); 
        
        trans=session.beginTransaction();
            Student stud=new Student();
            Parttime pt=new Parttime();
            Regular reg=new Regular();
            
            stud.setSname("Alpha");
            stud.setSdept("Robotics");
            stud.setId(2);
            
            pt.setSname("Beta");
            pt.setSdept("Models");
            pt.setPartimefees("20000");
            
            reg.setSname("Delta");
            reg.setSdept("Science");
            reg.setRegularfees("12000");
            
            session.save(pt);
            session.save(reg);
            session.save(stud);
            
            trans.commit();  
    } 
}

Output: