An Example of Table Per Hierarchy by using Annotations.
- Create the persistence classes and configuration file and also Create the class to stores the data..
Project Structure.
- Create the Persistance classes.
Payment.java
[java]package com.itoolsinfo;
import javax.persistence.Column;
import javax.persistence.DiscriminatorColumn;
import javax.persistence.DiscriminatorValue;
import javax.persistence.Entity;
import javax.persistence.GeneratedValue;
import javax.persistence.GenerationType;
import javax.persistence.Id;
import javax.persistence.Inheritance;
import javax.persistence.InheritanceType;
import javax.persistence.Table;
@Entity
@Table(name="SalaryDetails")
@Inheritance(strategy=InheritanceType.SINGLE_TABLE)
@DiscriminatorColumn(name="paymentmode")
@DiscriminatorValue(value="employee")
public class Payment
{
@Id
@GeneratedValue(strategy=GenerationType.AUTO)
private int paymentId;
@Column(name="amount")
private double amount;
public int getPaymentId() {
return paymentId;
}
public void setPaymentId(int paymentId) {
this.paymentId = paymentId;
}
public double getAmount() {
return amount;
}
public void setAmount(double amount) {
this.amount = amount;
}
}
[/java]
Discriminator is commonly used in SINGLE_TABLE inheritance because one can need a column to identify the type of the record. Every element bean will have an essential key, which you comment on the class with the @Id annotation. The essential key can be a solitary field or a mix of different fields relying upon your table structure.
As a matter of course, the @Id annotation will naturally decide the most suitable essential key era technique to be utilized however you can abrogate this by applying the @GeneratedValue explanation which takes two parameters system and generator.
CreditCard.java
[java]package com.itoolsinfo;
import javax.persistence.Column;
import javax.persistence.DiscriminatorValue;
import javax.persistence.Entity;
@Entity
@DiscriminatorValue("creditcard")
public class CreditCard extends Payment
{
@Column(name="cardNumber")
private int cardNumber;
@Column(name="cardType")
private String cardType;
public int getCardNumber() {
return cardNumber;
}
public void setCardNumber(int cardNumber) {
this.cardNumber = cardNumber;
}
public String getCardType() {
return cardType;
}
public void setCardType(String cardType) {
this.cardType = cardType;
}
}[/java]
The @Column annotation is utilized to indicate the points of interest of the segment to which a field or property will be mapped.
DebitCard.java
[java]package com.itoolsinfo;
import javax.persistence.Column;
import javax.persistence.DiscriminatorValue;
import javax.persistence.Entity;
@Entity
@DiscriminatorValue("debitcard")
public class DebitCard extends Payment
{
@Column(name="pinNumber")
private int pinNumber;
@Column(name="cardName")
private String cardName;
public int getPinNumber() {
return pinNumber;
}
public void setPinNumber(int pinNumber) {
this.pinNumber = pinNumber;
}
public String getCardName() {
return cardName;
}
public void setCardName(String cardName) {
this.cardName = cardName;
}
}
[/java]
The @Column explanation is utilized to indicate the points of interest of the segment to which a field or property will be mapped.
- Add the persistance classes in configuration file.
hibernate.cfg.xml
[xml]<?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="hibernate.hbm2ddl.auto">create</property>
<property name="dialect">org.hibernate.dialect.Oracle10gDialect</property>
<property name="connection.url">jdbc:oracle:thin:@localhost:1521:XE</property>
<!-- property name="connection.url">jdbc:oracle:thin:@127.0.0.1:1521:XE</property-->
<property name="connection.username">system</property>
<property name="connection.password">system</property>
<property name="connection.driver_class">oracle.jdbc.driver.OracleDriver</property>
<mapping class="com.iquickinfo.Payment"/>
<mapping class="com.iquickinfo.CreditCard"/>
<mapping class="com.iquickinfo.DebitCard"/>
</session-factory>
</hibernate-configuration>
[/xml]
| Properties |
Description |
| hibernate.connection.driver_class |
The JDBC driver class. |
| hibernate.dialect |
This property makes Hibernate generate the suitable SQL for the picked database. |
| hibernate.connection.url |
The JDBC URL to the database instance. |
| hibernate.connection.username |
The database username. |
| hibernate.connection.password |
The database password. |
| hibernate.connection.pool_size |
Limits the number of connections waiting in the Hibernate database connection pool. |
| hibernate.connection.autocommit |
Allows autocommit mode to be used for the JDBC connection. |
- Create the SPLessons class and stores the POJO Class objects.
SPLessons.java
[java]package com.itoolsnfo;
import org.hibernate.Session;
import org.hibernate.SessionFactory;
import org.hibernate.Transaction;
import org.hibernate.cfg.Configuration;
public class SPLessons
{
public static void main(String args[])
{
SessionFactory factory=new Configuration().configure().buildSessionFactory();
Session session=factory.openSession();
Payment payment=new Payment();
payment.setPaymentId(3);
payment.setAmount(20000);
CreditCard creditcard=new CreditCard();
creditcard.setCardNumber(5678);
creditcard.setCardType("visa");
DebitCard debitcard=new DebitCard();
debitcard.setPinNumber(6785);
debitcard.setCardName("KARUR VYSYA BANK");
Transaction transaction=session.beginTransaction();
session.save(payment);
session.save(creditcard);
session.save(debitcard);
transaction.commit();
session.close();
System.out.println("Payment datails all are entered using annotations");
}
}
[/java]
Database operations will be performed here.
Output:
Now check the database, result will be as follows.
Introduction 
