Basic hibernate code explanation

[ashwin bala]

The bean for first table is,

package roseindia;

public class Employee {

  private int id;
  private String name;
  private EmployeeAddress address;
  public int getId() {
    return id;
  }
  public void setId(int id) {
    this.id = id;
  }
  public String getName() {
    return name;
  }
  public void setName(String name) {
    this.name = name;
  }
  public EmployeeAddress getAddress() {
    address.setEmpid(getId());
    return address;
  }
  public void setAddress(EmployeeAddress address) {
    this.address = address;
  }
  
}

the bean for next table is

package roseindia;

public class EmployeeAddress {
  private int id;
  private int empid;
  private String address;
  private String country;
  public int getId() {
    return id;
  }
  public void setId(int id) {
    this.id = id;
  }
  public int getEmpid() {
    return empid;
  }
  public void setEmpid(int empid) {
    this.empid = empid;
  }
  public String getAddress() {
    return address;
  }
  public void setAddress(String address) {
    this.address = address;
  }
  public String getCountry() {
    return country;
  }
  public void setCountry(String country) {
    this.country = country;
  }
}

the Employee.hbm.xml file is

<?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="roseindia.Employee" table="employee">

<id name="id" type="int" column="employee_id" >

<generator class="native"/>

</id>

<property

name="name"

type="java.lang.String"

column="employee_name"

not-null="true"

length="50"

/>

<one-to-one name="address" class="roseindia.EmployeeAddress" property-ref="empid"

cascade="all"/>

</class>



<class name="roseindia.EmployeeAddress" table="employee_address">

<id name="id" type="int" column="id" >

<generator class="native"/>

</id>

<property

name="address"

type="java.lang.String"

column="address"

not-null="true"

length="255"

/>

<property

name="country"

type="java.lang.String"

column="country"

not-null="true"

length="100"

/>

<property

name="empid"

type="int"

column="emp_id"

not-null="true"

length="100"

/>

</class>

</hibernate-mapping>

the java file is

package roseindia;

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

public class OneToOneRelation {

  public static void main(String[] args) {

    SessionFactory sessFact=null;
    Session sess=null;
    try{
      sessFact=new Configuration().configure().buildSessionFactory();
      sess=sessFact.openSession();
      System.out.println("sess:"+sess);
      
      //Create Customer Object
      Employee emp = new Employee();    
      emp.setName("Deepak");
      
      //Create address object
      EmployeeAddress address = new EmployeeAddress();
      //Set some values
      address.setAddress("Delhi");
      address.setCountry("India");
      
      emp.setAddress(address);
      
      Transaction tr = sess.beginTransaction();
      sess.save(emp);
      tr.commit();
      
      System.out.println("Done");

    }
    catch (HibernateException he){
      System.out.println(he.getMessage());
    }
    finally{
      //SessionFactory close 
      sessFact.close();
      //Session close
      sess.close();
    }

  }

}

now can you please tell me what are the columns in the first and second table?
and also tell why emp_id is not filled but address and country are filled ?

i have implement hibernate in my application. help me with this issue.
Thanks in advance

[David Newton]

Nothing to do with Spring, moving to ORM.

[David Newton]

The columns are listed in your Hibernate mapping. IDs are usually generated--see the <generator> tag?

I'd suggest taking a step back and reading some Hibernate documentation and going through a tutorial or two before trying to proceed much further.

[Ryann Ong]

Hi Ashwin,

David is correct, Hibernate has its own feature of handling IDs by using the <generator> tag. The <generator> tag creates an identification for each Java class to generate unique identifiers for persistent class.

Here is a good link about Hibernate: http://docs.jboss.org/hibernate/core/3.3/reference/en/html/mapping.html#mapping-declaration-id