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Hibernate indexcolumn

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In this section, you will learn about the index column its utilization and implementation in Hibernate.

Hibernate indexcolumn

In this section, you will learn about the index column its utilization and implementation in Hibernate.

The index column is used to preserve the mapping order while retrieving.

In some applications order is very important. For this purpose, we use java.util.List. And also we added a column named as indx specially for this purpose. This column stores the index value for each column. This will help us in conserving order of records while retrieving.

The Project hierarchy is given below :

The SQL Query used to create employee  table is given below :

CREATE TABLE `employee` ( 
`employee_id` bigint(10) NOT NULL auto_increment, 
`firstname` varchar(50) default NULL, 
`lastname` varchar(50) default NULL, 
`cell_phone` varchar(15) default NULL, 
`address_id` bigint(20) default NULL, 
`indx` int(11) default NULL, 
PRIMARY KEY (`employee_id`), 
KEY `FK_employee` (`address_id`), 
CONSTRAINT `FK_employee` FOREIGN KEY (`address_id`) REFERENCES `address` (`address_id`) 
) ENGINE=InnoDB DEFAULT CHARSET=latin1 

The SQL query used to create address table is given below :

CREATE TABLE `address` ( 
`address_id` bigint(20) NOT NULL auto_increment, 
`street` varchar(50) default NULL, 
`city` varchar(50) default NULL, 
`state` varchar(50) default NULL, 
`country` varchar(50) default NULL, 
PRIMARY KEY (`address_id`) 
) ENGINE=InnoDB DEFAULT CHARSET=latin1 

CODE

hibernate.cfg.xml( /src/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>
<!-- Database connection settings -->
<property name="connection.driver_class">com.mysql.jdbc.Driver</property>
<property name="connection.url">jdbc:mysql://192.168.10.13:3306/anky</property>
<property name="connection.username">root</property>
<property name="connection.password">root</property>

<property name="connection.pool_size">1</property>
<property name="dialect">org.hibernate.dialect.MySQLDialect</property>
<property name="current_session_context_class">thread</property>
<property name="cache.provider_class">org.hibernate.cache.NoCacheProvider</property>
<property name="show_sql">true</property>
<property name="hbm2ddl.auto">validate</property>

<mapping class="net.roseindia.Address" />
<mapping class="net.roseindia.Employee" />

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

Address.java( /src/net/roseindia/Address.java )

In the below code, you can see that we annotate the employees list using  @IndexColumn(name="indx") :

package net.roseindia;

import java.util.List;

import javax.persistence.CascadeType;
import javax.persistence.Column;
import javax.persistence.Entity;
import javax.persistence.GeneratedValue;
import javax.persistence.Id;
import javax.persistence.JoinColumn;
import javax.persistence.OneToMany;
import javax.persistence.Table;

import org.hibernate.annotations.IndexColumn;

@Entity
@Table(name = "address")
public class Address {
@Id
@GeneratedValue
@Column(name = "address_id")
private Long addressId;

@Column(name = "street")
private String street;

@Column(name = "city")
private String city;

@Column(name = "state")
private String state;

@Column(name = "country")
private String country;

@OneToMany(cascade={CascadeType.ALL})
@JoinColumn(name="address_id")
@IndexColumn(name="indx")
private List<Employee> employees;

public Long getAddressId() {
return addressId;
}

public void setAddressId(Long addressId) {
this.addressId = addressId;
}

public String getStreet() {
return street;
}

public void setStreet(String street) {
this.street = street;
}

public String getCity() {
return city;
}

public void setCity(String city) {
this.city = city;
}

public String getState() {
return state;
}

public void setState(String state) {
this.state = state;
}

public String getCountry() {
return country;
}

public void setCountry(String country) {
this.country = country;
}

public List<Employee> getEmployees() {
return employees;
}

public void setEmployees(List<Employee> employees) {
this.employees = employees;
}
}

Employee.java ( /src/net/roseindia/Employee.java )

package net.roseindia;

import javax.persistence.Column;
import javax.persistence.Entity;
import javax.persistence.GeneratedValue;
import javax.persistence.Id;
import javax.persistence.JoinColumn;
import javax.persistence.ManyToOne;
import javax.persistence.Table;

@Entity
@Table(name="employee")
public class Employee {
@Id
@GeneratedValue
@Column(name="employee_id")
private Long employeeId;

@Column(name="firstname")
private String firstname;

@Column(name="lastname")
private String lastname;

@Column(name="cell_phone")
private String cellphone;

@ManyToOne
@JoinColumn(name="address_id")
private Address address;

public Address getAddress() {
return address;
}

public void setAddress(Address address) {
this.address = address;
}

public Employee() {}

public Employee(String firstname, String lastname, String phone) {
this.firstname = firstname;
this.lastname = lastname;
this.cellphone = phone;
}

public Long getEmployeeId() {
return employeeId;
}

public void setEmployeeId(Long employeeId) {
this.employeeId = employeeId;
}

public String getFirstname() {
return firstname;
}

public void setFirstname(String firstname) {
this.firstname = firstname;
}

public String getLastname() {
return lastname;
}

public void setLastname(String lastname) {
this.lastname = lastname;
}

public String getCellphone() {
return cellphone;
}

public void setCellphone(String cellphone) {
this.cellphone = cellphone;
}
}

ManageEmployee.java ( /src/net/roseindia/ManageEmployee.java )

package net.roseindia;

import java.util.ArrayList;

import org.hibernate.Session;
import org.hibernate.SessionFactory;
import org.hibernate.cfg.Configuration;
import org.hibernate.service.ServiceRegistry;
import org.hibernate.service.ServiceRegistryBuilder;

public class ManageEmployee {
private static SessionFactory sf;
private static ServiceRegistry serviceRegistry;

public static void main(String[] args) {
try {
Configuration configuration = new Configuration();
configuration.configure();
serviceRegistry = new ServiceRegistryBuilder().applySettings(
configuration.getProperties()).buildServiceRegistry();
sf = configuration.buildSessionFactory(serviceRegistry);
} catch (Throwable ex) {
System.err.println("Failed to create sessionFactory object." + ex);
throw new ExceptionInInitializerError(ex);
}
System.out.println("------------One To Many Indexed mapping---------");
Session session = sf.openSession();
session.beginTransaction();

Address address = new Address();
address.setStreet("West Bank");
address.setCity("New Delhi");
address.setState("Delhi");
address.setCountry("India");

Employee e1 = new Employee("Romesh", "Thapar", "9999999999");
Employee e2 = new Employee("Smita", "Khanna", "3333333333");

address.setEmployees(new ArrayList<Employee>());
address.getEmployees().add(e1);
address.getEmployees().add(e2);

session.save(address);

session.getTransaction().commit();
session.close();
}
}

In console, you will get the following output :

------------One To Many Indexed mapping---------
Hibernate: insert into address (city, country, state, street) values (?, ?, ?, ?)
Hibernate: insert into employee (address_id, cell_phone, firstname, lastname) values (?, ?, ?, ?)
Hibernate: insert into employee (address_id, cell_phone, firstname, lastname) values (?, ?, ?, ?)
Hibernate: update employee set address_id=?, indx=? where employee_id=?
Hibernate: update employee set address_id=?, indx=? where employee_id=?

In employee table, you will get the following record :

In address table, you will get the following record :

Download Source Code

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Posted on: April 19, 2012

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