Wednesday, 24 December 2014

Set table name for entity in Hibernate


By default, Hibernate takes unqualified class name as table name. Entity annotation provides attribute “name”, using this you can override the default table name given to this entity.

hibernate.cfg.xml
<?xml version='1.0' encoding='utf-8'?>
<!DOCTYPE hibernate-configuration PUBLIC
        "-//Hibernate/Hibernate Configuration DTD 3.0//EN"
        "http://www.hibernate.org/dtd/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://localhost/sample</property>
    <property name="connection.username">root</property>
    <property name="connection.password">tiger</property>
    
    <!-- Enable the logging of all the generated SQL statements to the console -->
    <property name="show_sql">true</property>
    
    <!-- Format the generated SQL statement to make it more readable, -->
    <property name="format_sql">false</property>
    
    <!-- Hibernate will put comments inside all generated SQL statements to hint what’s the generated SQL trying to do -->
    <property name="use_sql_comments">false</property>
    
    <!-- This property makes Hibernate generate the appropriate SQL for the chosen database. -->
    <property name="dialect">org.hibernate.dialect.MySQLDialect</property>
    
    <!-- Drop and re-create the database schema on startup -->
    <property name="hbm2ddl.auto">create</property>
    
    <!-- mappings for annotated classes -->
    <mapping class="myFirstHibernate.Employee" />
    
  </session-factory>
  
</hibernate-configuration>

package myFirstHibernate;

import javax.persistence.Entity;
import javax.persistence.Id;

@Entity(name="employee_details")
public class Employee {
 @Id
 private int id;
 private String firstName;
 private String lastName;
 private String designation;
 private int age;
 private double salary;
 
 public Employee(int id, String firstName, String lastName,
   String designation, int age, double salary) {
  super();
  this.id = id;
  this.firstName = firstName;
  this.lastName = lastName;
  this.designation = designation;
  this.age = age;
  this.salary = salary;
 }
 
 public int getId() {
  return id;
 }
 
 public void setId(int id) {
  this.id = id;
 }
 
 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 getDesignation() {
  return designation;
 }
 
 public void setDesignation(String designation) {
  this.designation = designation;
 }
 
 public int getAge() {
  return age;
 }
 
 public void setAge(int age) {
  this.age = age;
 }
 
 public double getSalary() {
  return salary;
 }
 
 public void setSalary(double salary) {
  this.salary = salary;
 }
 
}

package myFirstHibernate;

import org.hibernate.Session;
import org.hibernate.SessionFactory;
import org.hibernate.boot.registry.StandardServiceRegistryBuilder;
import org.hibernate.cfg.Configuration;


public class TestEmployee {
 
 /* Step 1: Create session factory */
 private static SessionFactory getSessionFactory() {
  Configuration configuration = new Configuration().configure();
  StandardServiceRegistryBuilder builder = new StandardServiceRegistryBuilder().
  applySettings(configuration.getProperties());
  SessionFactory factory = configuration.buildSessionFactory(builder.build());
        return factory;
    }
 
 public static void main(String args[]){
  Employee emp1 = new Employee(1, "Hari Krishna", "Gurram", "Senior Software Developer", 26, 80000);
  Employee emp2 = new Employee(2, "Shreyas", "Desai", "Team Manager", 35, 150000);
  Employee emp3 = new Employee(3, "Piyush", "Rai", "Senior Software Developer", 26, 100000);
  Employee emp4 = new Employee(4, "Maruti", "Borker", "Software Developer", 26, 60000);
  
  SessionFactory sessionFactory = getSessionFactory();
  Session session = sessionFactory.openSession();
  session.beginTransaction();
  session.save(emp1);
  session.save(emp2);
  session.save(emp3);
  session.save(emp4);
  session.getTransaction().commit();
  session.close();  
 }
}

Run TestEmployee.java, you will see output like below in console.

Hibernate: drop table if exists employee_details
Hibernate: create table employee_details (id integer not null, age integer not null, designation varchar(255), firstName varchar(255), lastName varchar(255), salary double precision not null, primary key (id))
Dec 19, 2014 10:30:11 PM org.hibernate.tool.hbm2ddl.SchemaExport execute
INFO: HHH000230: Schema export complete
Hibernate: insert into employee_details (age, designation, firstName, lastName, salary, id) values (?, ?, ?, ?, ?, ?)
Hibernate: insert into employee_details (age, designation, firstName, lastName, salary, id) values (?, ?, ?, ?, ?, ?)
Hibernate: insert into employee_details (age, designation, firstName, lastName, salary, id) values (?, ?, ?, ?, ?, ?)
Hibernate: insert into employee_details (age, designation, firstName, lastName, salary, id) values (?, ?, ?, ?, ?, ?)


As you observe, now the table name changed as “employee_details”.


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