Hi,

I am new to Hibernate. I am trying to implement Uni-directional mappings by using two class Parent and Child.

package com.sen;

import java.util.Set;

package com.sen;

import java.util.Set;

public class Parent {
private long id;
private Set Children;
public Set getChildren() {return Children;}
public void setChildren(Set children) { Children = children;}
public long getId() {return id; }
public void setId(long id) {this.id = id;}
}

<?xml version="1.0"?>
<!DOCTYPE hibernate-mapping PUBLIC
"-//Hibernate/Hibernate Mapping DTD 3.0//EN"
"http://hibernate.sourceforge.net/hibernate-mapping-3.0.dtd">

<hibernate-mapping>
<class name="com.sen.Parent" table="parent">
<id name="id" type="long" column="pid"/>
<!-- <generator class="native" />
</id> -->
<set name="children" inverse="false" cascade="none">
<key column="pid" />
<one-to-many column="cid" class="com.sen.Child" />
</set>
</class>
</hibernate-mapping>

-----------------------------

package com.sen;

package com.sen;

public class Child {
private long id;
private String firstName;
private String lastName;
public String getFirstName() {return firstName; }
public void setFirstName(String firstName) {this.firstName = firstName; }
public long getId() {return id; }
public void setId(long id) {this.id = id;}
public String getLastName() {return lastName;}
public void setLastName(String lastName) {this.lastName = lastName;}
}


<?xml version="1.0"?>
<!DOCTYPE hibernate-mapping PUBLIC
"-//Hibernate/Hibernate Mapping DTD 3.0//EN"
"http://hibernate.sourceforge.net/hibernate-mapping-3.0.dtd">

<hibernate-mapping>
<class name="com.sen.Child" table="child">
<id name="id" type="long" column="cid" />
<!-- <generator class="native" />
</id> -->
<property name="firstName" column="firstName" />
<property name="lastName" column="lastName" />
</class>
</hibernate-mapping>

------------------------


The client program for the same as given below.

package com.sen;
import java.io.*;
import java.util.*;
import org.hibernate.Session;
import org.hibernate.SessionFactory;
import org.hibernate.Transaction;
import org.hibernate.cfg.Configuration;

public class AssociationClient {

public static void main(String ar[]){

try{

System.out.println("11111111");
File f=new File("D:\\sen\\springapp\\src\\com\\association\\hibernate.cfg.xml");
System.out.println("f.getAbsolutePath()==>"+f.getAbsolutePath());
Configuration cfg = new Configuration().addFile(f);
System.out.println("22222222");
SessionFactory sessionFactory = cfg.configure().buildSessionFactory();
Session session =sessionFactory.openSession();
System.out.println("33333333");
Transaction transaction = session.beginTransaction();
//List list = query.list();
//The insertion to be done here.


//Parent set up.
Parent parent = new Parent();
System.out.println("4444444");
//create child 1.
Child child1 = new Child();
child1.setFirstName("John");
child1.setLastName("Smith");

// create the set of children.
Set children = new HashSet();

children.add(child1);
System.out.println("555555");

// create child 2.
/*Child child2 = new Child();
child2.setFirstName("John");
child2.setLastName("Wright");
children.add(child2);*/

parent.setChildren(children);
System.out.println("6666666");
session.saveOrUpdate(child1);
System.out.println("777777");
session.saveOrUpdate(parent);

transaction.commit();

}catch(Exception e){
System.out.println(e.getMessage());
System.out.println(e);

}
}
}

-----------------------
I am getting the following output.

11111111
f.getAbsolutePath()==>D:\sen\springapp\src\com\association\hibernate.cfg.xml
33333333
4444444
555555
6666666
Hibernate: select child_.cid, child_.firstName as firstName1_, child_.lastName as lastName1_ from child child_ where child_.cid=?
could not retrieve snapshot: [com.sen.Child#0]
org.hibernate.exception.GenericJDBCException: could not retrieve snapshot: [com.sen.Child#0]


-----------------------

Kindly help me in this regard.