(Beginner) foreign key mapping issue

ozdemit · **Joined:** Fri Aug 14, 2009 6:20 am **Posts:** 5

Hi folks,

I did not know a good title for my question. I hope my problem related to this group too. I have a sample project and two objects called User and UserDetail. I want a normal select query with a given user id then see all user information and details in a row.

When I debug my project, I can see user information is ready but UserDetails are null. What did I do wrongly? Here is my sample code...

my user object

Code:

package net.tolgaozdemir.client.dto;

import java.io.Serializable;


public class User implements Serializable {

   /**
    * 
    */
   private static final long serialVersionUID = -3336917240964722630L;
   private int id;
   private String username;
   private String password;
   private String email;
   private UserDetail userdetail;
   
   
   
   public UserDetail getUserdetail() {
      return userdetail;
   }
   public void setUserdetail(UserDetail userdetail) {
      this.userdetail = userdetail;
   }
   
   public String getEmail() {
      return email;
   }
   public void setEmail(String email) {
      this.email = email;
   }
   public int getId() {
      return id;
   }
   public void setId(int id) {
      this.id = id;
   }
   public String getUsername() {
      return username;
   }
   public void setUsername(String username) {
      this.username = username;
   }
   public String getPassword() {
      return password;
   }
   public void setPassword(String password) {
      this.password = password;
   }
      
}

my user detail object

Code:

package net.tolgaozdemir.client.dto;

import java.io.Serializable;

public class UserDetail  implements Serializable {

   /**
    * 
    */
   private static final long serialVersionUID = -8035616118364001074L;
   private int id;
   private String location;
   private String birthday;
   
   public int getId() {
      return id;
   }
   public void setId(int id) {
      this.id = id;
   }
   
   
   public String getLocation() {
      return location;
   }
   public void setLocation(String location) {
      this.location = location;
   }
   
   public String getBirthday() {
      return birthday;
   }
   public void setBirthday(String birthday) {
      this.birthday = birthday;
   }
   
   public UserDetail(){}
   
}

and hibernate map files

Code:

<hibernate-mapping package="net.tolgaozdemir.client.dto" >
   
  <class name="User" table="tbluser" > 
        
        <id name="id" column="id" type="integer">  
              <generator class="native"/>
        </id> 
        <property name="username" column="username" type="string" />
        <property name="password" column="password"  type="string" />
        <property name="email" column="email"  type="string" />
        <many-to-one name="userdetail" column="userdetail_id" class="UserDetail" />
     
  </class>
  
</hibernate-mapping>

Code:

<hibernate-mapping package="net.tolgaozdemir.client.dto" >
   
  <class name="UserDetail" table="tbluserdetails" lazy="true"  > 
        
        <id name="id" column="id" type="integer">  
              <generator class="native"/>
        </id> 
        <property name="location" column="location" type="string" />
        <property name="birthday" column="birthday"  type="string" />
        
  </class>
  
</hibernate-mapping>

Regards,

Tolga

tarun walia · **Joined:** Sat Aug 01, 2009 5:28 am **Posts:** 42

u r mappings are not correct.better if u take a look at association and collections

Cameron McKenzie · **Posted:** Wed Sep 02, 2009 6:37 am

Check out this little tutorial on one-to-one mappings with Hibernate:

http://jpa.ezhibernate.com/Javacode/learn.jsp?tutorial=17mappingonetooneassociations

I use an Exam and ExamDetail in the example, but it's similar:

Code:

@Entity
@Table(name = "exam", schema = "examscam")
public class Exam {
/* @Basic annotation has been
 added to all basic fields*/
 
  private int id;
  private String shortName;

  private ExamDetail detail;

  @Id
  @GeneratedValue
  @Column(name = "id")
  public int getId() { return id; }
  private void setId(int id) {this.id = id;}

 @OneToOne(cascade=CascadeType.ALL,fetch=FetchType.LAZY)
  @JoinColumn(name="detail_id")
  public ExamDetail getDetail() {return detail; }
  public void setDetail(ExamDetail detail) {
    this.detail = detail;
  }   

  @Basic
  public String getShortName() { return shortName;}
  public void setShortName(String shortName) {
    this.shortName = shortName;
  }
}

Code:

@Entity
@Table(name = "exam_detail", schema = "examscam")
public class ExamDetail {
/* @Basic annotation has been 
added to all basic fields*/
  private int id;
  private String fullName;
  private int numberOfQuestions;
  private int passingPercentage;  
  private Exam exam;
  
  @Id
  @GeneratedValue
  @Column(name = "id")
  public int getId() {return id;}
  private void setId(int id) {this.id = id;}

  @OneToOne(cascade=CascadeType.ALL, mappedBy="detail")
  public Exam getExam(){return exam;}
  public void setExam(Exam exam){this.exam=exam;}

  @Basic
  public String getFullName() {return fullName;}
  public void setFullName(String fullName) {
    this.fullName = fullName;
  }

  @Basic
  public int getNumberOfQuestions() {
   return numberOfQuestions;
  }
 public void setNumberOfQuestions(int numberOfQuestions){
    this.numberOfQuestions = numberOfQuestions;
  }

  @Basic
  public int getPassingPercentage() {
   return passingPercentage;
  }
  public void setPassingPercentage(int passingPercentage){
    this.passingPercentage = passingPercentage;
  }
}