Hibernate One to Many Mapping Delete Query Example

Let us see the logic for hibernate one to many mapping delete query, Actually every thing is same like Hibernate One-to-Many Mapping Insert  but only change is in OurLogic.java file.

But mates, ensure you came through these sessions for better understand

• Hibernate One-to-Many Mapping Insert 
• Hibernate Relationships In Depth

Files required..

• Vendor.java [pojo class]
• Customer.java [pojo class]
• OurLogic.java
• Customer.hbm.xml
• hibernate.cfg.xml
• Vendor.hbm.xml

Vendor.java

123456789101112131415161718192021222324252627282930package str;

import java.util.Set;

public class Vendor {

private int vendorId;
private String vendorName;

private Set children;

public int getVendorId() { return vendorId; } public void setVendorId(int vendorId) { this.vendorId = vendorId; } public String getVendorName() { return vendorName; } public void setVendorName(String vendorName) { this.vendorName = vendorName; } public Set getChildren() { return children; } public void setChildren(Set children) { this.children = children; } }

Customer.java

12345678910111213141516171819202122232425262728package str;
public class Customer {

private int customerId;
private String customerName;

private int forevenId;

public int getCustomerId() { return customerId; } public void setCustomerId(int customerId) { this.customerId = customerId; } public String getCustomerName() { return customerName; } public void setCustomerName(String customerName) { this.customerName = customerName; } public int getForevenId() { return forevenId; } public void setForevenId(int forevenId) { this.forevenId = forevenId; } }

Customer.hbm.xml

123456789101112131415<?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="str.Customer" table="customer">

<id name="customerId" column="custid"  />
<property name="customerName" column="custname" length="10"/>

<property name="forevenId" column="forevenid" insert="false" />

</class> </hibernate-mapping>

Vendor.hbm.xml

1234567891011121314151617181920<?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="str.Vendor" table="vendor">

<id name="vendorId" column="vendid"  />
<property name="vendorName" column="vendname" length="10"/>

<set name="children" cascade="all" >

<key column="forevenid" />

<one-to-many class="str.Customer" />

</set>

</class> </hibernate-mapping>

hibernate.cfg.xml

123456789101112131415161718192021<?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 resource="Customer.hbm.xml"></mapping>
<mapping resource="Vendor.hbm.xml"></mapping>
</session-factory>
</hibernate-configuration>

Deleting Single Parent Object With All Child

OurLogic.java

12345678910111213141516171819202122232425262728293031package str;

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

public class OurLogic {

public static void main(String args[])
{

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

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

Object o = session.get(Vendor.class, new Integer(101));
Vendor v = (Vendor)o;

Transaction tx = session.beginTransaction();
session.delete(v);
tx.commit();

session.close();
System.out.println("One To Many is Done for deleting..!!");
factory.close();

}
}

If we want to delete all the parent objects will all its corresponding child objects., then the logic will be like..

Deleting All Parent Objects With All Childs

OurLogic.java

1234567891011121314151617181920212223242526272829303132333435363738394041424344package str;

import java.util.Iterator;
import java.util.List;

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

public class OurLogic {

public static void main(String args[])
{

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

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

Query qry =session.createQuery("from Vendor v");
List l=qry.list();
Iterator it = l.iterator();

Transaction tx = session.beginTransaction();

while(it.hasNext())
{

Object o = it.next();
Vendor v = (Vendor) o;
session.delete(v);
}

tx.commit();

session.close();
System.out.println("One To Many is Done for deleting all parents with childs...!");
factory.close();

}