Different Mapping Types in Hibernate

[Rajendra Prakash]

One-to-One mapping means one pojo mapped with one table ,is it .
i read tutorials , but it was confusing.

[Sridhar Santhanakrishnan]

What tutorials did you read? A mapping refers to relationship between entities.

Look at this for more detail. one-one mapping

[Rajendra Prakash]

I already saw this link. For one-to-one mapping why many-to-one is specified

<?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.sample.employee.Employee" table="EMPLOYEE_DETAILS">
<id name="employeeId" type="long" column="EMPLOYEE_ID" >
<generator class="assigned"/>
</id>
<property name="employeeName">
<column name="EMPLOYEE_NAME" />
</property>
<property name="salary">
<column name="SALARY"/>
</property>

<many-to-one name="parkingSpace" class = "com.sample.employee.ParkingSpace" column="PARKING_SPACE_ID" unique="true" />

</class>
</hibernate-mapping>

[Eduardo Yañez Parareda]

Rajendra Prakash wrote:One-to-One mapping means one pojo mapped with one table ,is it .
i read tutorials , but it was confusing.

Don't read tutorials, read the reference manual. This chapter explains what a mapping is and the relationships.
http://docs.jboss.org/hibernate/core/3.3/reference/en/html/mapping.html

[Sridhar Santhanakrishnan]

I meant the scenario that the OP described.

I have an Employee object and a Parking Space Object. The have a one to one relation i.e., an employee will always be associated to only one parking space, that parking space should not be associated to any other employee.

[Cameron Wallace McKenzie]

One to one infers the relationship between objects, not the relationship between the object and the table.

Here is an example of a one-to-one mapping between objects, but both objects link to the same database table.



Tutorial on Mapping Two Classes to One Table

  
package com.examscam.mappings;
import javax.persistence.*;
import org.hibernate.Session;
import com.examscam.HibernateUtil;

@Entity
public class Thing {
  private long id;  
  private String name;

  private ThingDetail thingDetail;

 @Embedded
  public ThingDetail getThingDetail(){
    return thingDetail;
  }
  public void setThingDetail(ThingDetail detail) {
    this.thingDetail = detail;
  }

  @Id
  @GeneratedValue
  public long getId() {return id;}
  public void setId(long id) {this.id = id;}

  public String getName() {return name;}
  public void setName(String name) {this.name = name;}
}