Hibernate One to Many Mapping Example

package com.hibernate.venkat;

import java.util.List;

import javax.persistence.CascadeType;
import javax.persistence.Entity;
import javax.persistence.FetchType;
import javax.persistence.GeneratedValue;
import javax.persistence.Id;
import javax.persistence.OneToMany;

@Entity
public class College {


private int collegeId;
private String collegeName;
private List<Student> students;

@Id
@GeneratedValue
public int getCollegeId() {
return collegeId;
}
public void setCollegeId(int collegeId) {
this.collegeId = collegeId;
}
public String getCollegeName() {
return collegeName;
}
public void setCollegeName(String collegeName) {
this.collegeName = collegeName;
}
@OneToMany(targetEntity=Student.class,mappedBy="college",cascade=CascadeType.ALL,fetch=FetchType.LAZY)
public List<Student> getStudents() {
return students;
}
public void setStudents(List<Student> students) {
this.students = students;
}
@Override
public String toString() {
return "College [collegeId=" + collegeId + ", collegeName="
+ collegeName + ", students=" + students + "]";
}



}

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package com.hibernate.venkat;

import javax.persistence.Entity;

import javax.persistence.GeneratedValue;

import javax.persistence.Id;

import javax.persistence.JoinColumn;

import javax.persistence.ManyToOne;

@Entity

public class Student {

private int studentId;

private String studentName;

private College  college;

@Id

@GeneratedValue

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;

}

@ManyToOne

@JoinColumn(name="College_id")

public College getCollege() {

return college;

}

public void setCollege(College college) {

this.college = college;

}

}

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/**

 * 

 */

package com.hibernate.venkat;

import org.hibernate.Session;

import org.hibernate.SessionFactory;

import org.hibernate.cfg.AnnotationConfiguration;

import org.hibernate.tool.hbm2ddl.SchemaExport;

/**

 * @author Venkat

 *

 */

public class TestOneToMany {

/**

* @param args

*/

public static void main(String[] args) {

// TODO Auto-generated method stub

AnnotationConfiguration config=new AnnotationConfiguration();

config.addAnnotatedClass(College.class);

config.addAnnotatedClass(Student.class);

config.configure();

new SchemaExport(config).create(true, true);

SessionFactory sf= config.buildSessionFactory();

Session s=sf.getCurrentSession();

s.beginTransaction();

College c=new College();

c.setCollegeName("Georgia TECH");

Student s1=new Student();

s1.setStudentName("Venkat");

s1.setCollege(c);

Student s2=new Student();

s2.setStudentName("Sunil");

s2.setCollege(c);

s.save(c);

s.save(s1);

s.save(s2);

s.getTransaction().commit();

}

}

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<?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>

        <!-- Database connection settings -->

        <property name="connection.driver_class">oracle.jdbc.OracleDriver</property>

        <property name="connection.url">jdbc:oracle:thin:@localhost:1521:xe</property>

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

        <property name="connection.password">venkat</property>

        <!-- JDBC connection pool (use the built-in) -->

        <property name="connection.pool_size">2</property>

        <!-- SQL dialect -->

        <property name="dialect">org.hibernate.dialect.Oracle10gDialect</property>

        <!-- Enable Hibernate's current session context -->

        <property name="current_session_context_class">thread</property>

        <!-- Disable the second-level cache  -->

        <property name="cache.provider_class">org.hibernate.cache.NoCacheProvider</property>

        <!-- Echo all executed SQL to stdout -->

        <property name="show_sql">true</property>

        <!-- Drop and re-create the database schema on startup -->

<!--         <property name="hbm2ddl.auto">create</property> -->

<!--         <mapping resource="org/hibernate/tutorial/domain/Event.hbm.xml"/> -->

<!--         <mapping resource="org/hibernate/tutorial/domain/Person.hbm.xml"/> -->

    </session-factory>

</hibernate-configuration>