Table Per Subclass

In case of Table Per Subclass, subclass mapped tables are related to parent class mapped table by primary key and foreign key relationship.

POJO CLASS
public class Emp {
private int id;
private String name;
public int getId() {
return id;
}
public void setId(int id) {
this.id = id;
}
public String getName() {
return name;
}
public void setName(String name) {
this.name = name;
}


}
CHILD CLASS
package beans;

public class Con_Emp extends Emp{

private int pey_per_hour;
private String contract_duration;
public int getPey_per_hour() {
return pey_per_hour;
}
public void setPey_per_hour(int pey_per_hour) {
this.pey_per_hour = pey_per_hour;
}
public String getContract_duration() {
return contract_duration;
}
public void setContract_duration(String contract_duration) {
this.contract_duration = contract_duration;
}


}

CHILD CLASS

package beans;

public class Reg_Emp extends Emp{

private int salary;

private int bonus;

public int getSalary() {

return salary;

}

public void setSalary(int salary) {

this.salary = salary;

}

public int getBonus() {

return bonus;

}

public void setBonus(int bonus) {

this.bonus = bonus;

}

}

emp.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="beans.Emp" table="tps1">

          <id name="id">

          <generator class="increment"/></id>

          <property name="name"/>

          </class>

          <joined-subclass name="beans.Con_Emp" table="tps2">

          <key column="eid"/>

          <property name="pey_per_hour"/>

          <property name="contract_duration"></property>

          </joined-subclass>

          <joined-subclass name="beans.Reg_Emp" table="tps3">

          <key column="eid"/>

          <property name="bonus"/>

          <property name="salary"/>

          </joined-subclass>

          

          </hibernate-mapping>

Configuration file

<?xml version='1.0' encoding='UTF-8'?> 

<!DOCTYPE hibernate-configuration PUBLIC 

          "-//Hibernate/Hibernate Configuration DTD 3.0//EN" 

          "http://hibernate.sourceforge.net/hibernate-configuration-3.0.dtd">

          <hibernate-configuration>

          <session-factory>

          <property name="hbm2ddl.auto">update</property>

<property name="dialect">org.hibernate.dialect.MySQLDialect</property> 

<property name="connection.url">jdbc:mysql://localhost:3306/db</property> 

        <property name="connection.username">root</property> 

        <property name="connection.password">lk@9616918397y</property> 

        <property name="connection.driver_class">com.mysql.jdbc.Driver</property> 

   <mapping resource="rsc/emp.hbm.xml"/>

         

          </session-factory>

          </hibernate-configuration>

Test class

package test;

import org.hibernate.Session;

import org.hibernate.SessionFactory;

import org.hibernate.Transaction;

import org.hibernate.cfg.Configuration;

import beans.Con_Emp;

import beans.Emp;

import beans.Reg_Emp;

public class Test {

public static void main(String[] args) {

Configuration cfg=new Configuration();

 cfg.configure("rsc/configuration.cfg.xml");

 

 SessionFactory sf=cfg.buildSessionFactory();

 Session s=sf.openSession();

 Transaction t=s.beginTransaction();

 

 Emp employee=new Emp();

 Con_Emp con=new Con_Emp();

 Reg_Emp  reg=new Reg_Emp();

 employee.setId(1);

 employee.setName("lk");

 con.setId(2);

 con.setName("bjvb");

 con.setContract_duration("3 years");

 con.setPey_per_hour(23);

 reg.setId(3);

 reg.setName("dbfjubgv");

 reg.setBonus(2000);

 reg.setSalary(4000);

 t.commit();

 s.close();

 System.out.println("all is right");

}

}