Hibernate One To One Mapping Using Annotations

Let us see the example on one to one mapping using annotations..

Files required…

• Address.java
• Student.java
• hibernate.cfg.xml
• ClientForSave.java

Address.java

package str;

import javax.persistence.CascadeType;
import javax.persistence.Column;
import javax.persistence.Entity;
import javax.persistence.Id;
import javax.persistence.JoinColumn;
import javax.persistence.OneToOne;
import javax.persistence.Table;

@Entity
@Table(name="Address")
public class Address {
	@Id
	@Column(name="addrid")
	private  int addressId;

	@Column(name="place",length=10)
	private String place;

	@OneToOne(targetEntity=Student.class,cascade=CascadeType.ALL)
	@JoinColumn(name="stu_id",referencedColumnName="sid")
	private  Student  parent;

	public int getAddressId() {
		return addressId;
	}
	public void setAddressId(int addressId) {
		this.addressId = addressId;
	}
	public String getPlace() {
		return place;
	}
	public void setPlace(String place) {
		this.place = place;
	}
	public Student getParent() {
		return parent;
	}
	public void setParent(Student parent) {
		this.parent = parent;
	}

}

Student.java

package str;

import javax.persistence.Column;
import javax.persistence.Entity;
import javax.persistence.Id;
import javax.persistence.Table;

@Entity
@Table(name="students")
public class Student {
	@Id
	@Column(name="sid")
	private int studentId;

	@Column(name="sname", length=10)
	private String studentName;

	@Column(name="grp",length=10)
	private String grp;

	public String getGrp() {
		return grp;
	}
	public void setGrp(String grp) {
		this.grp = grp;
	}
	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;
	}

}

hibernate.cfg.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="connection.driver_class">oracle.jdbc.driver.OracleDriver
</property>
<property name="connection.url">jdbc:oracle:thin:@www.java4s.com:1521:XE</property>
<property name="connection.username">system</property>
<property name="connection.password">admin</property>

<property name="dialect">org.hibernate.dialect.OracleDialect</property>
<property name="show_sql">true</property>
<property name="hbm2ddl.auto">update</property>

<mapping></mapping>
<mapping></mapping>
</session-factory>
</hibernate-configuration>

ClientForSave.java

package str;

import org.hibernate.Session;
import org.hibernate.SessionFactory;
import org.hibernate.Transaction;
import org.hibernate.cfg.Configuration;

public class ClientForSave {
	public  static  void main(String args[])
	{

		Configuration cfg=new Configuration();
	    cfg.configure("hibernate.cfg.xml");	        

	    SessionFactory factory = cfg.buildSessionFactory();
	    Session session = factory.openSession();

		Student  s = new Student();
		s.setStudentId(101);
		s.setStudentName("James");
		s.setGrp("mpc");

		Address  ad = new Address();
		ad.setAddressId(1);
		ad.setPlace("Carolina");

		ad.setParent(s);
		Transaction  tx = session.beginTransaction();
		session.save(ad);
		tx.commit();
		session.close();
		System.out.println("One to One with annotations is done..!!!!");
		factory.close();
	}
}

Eclipse Output

In the database

What you are thinkig....