one-to-one with manually assigned identifiers

nelsonhh · **Joined:** Thu Sep 08, 2005 2:14 pm **Posts:** 7

one-to-one with manually assigned identifiers

I have a troubles with a one-to-one mapping.

I read the half day through the forums, but couldn't find an appropriate answer.

using hibernate 3.1 beta 2 with annotations 3.1 beta 4

I manually assign guids as my id.

I have an unidirectional one-to-one mapping from class A to class B.

The generated schema includes an foreign key constraint in table A to the primary key in table B.

I configured versioning with int as type. During object instanciation the guid as id is generated by the constructor and zero value ist assigned to version.

In the one-to-one mapping I have defined Cascade.ALL

when i try the following a foreign key violation occurs:

B b = new B();

A a = new A();
a.setB(b);

saverOrUpdate(A);

From what I read from the reference guide about automatic state detection, I would not expect any trouble. Hibernate should recognize, that A AND B are transient and insert it.

Here is the code:

Code:

@Entity
@Table
public class A {
   protected String id;
   protected int version;
   protected B b;
   
   public A() {
      super();
      id = java.util.UUID.randomUUID().toString();
      version = 0;
   }
   
   
   /**
    * I also tried CascadeType.ALL
    */
   @OneToOne(targetEntity=B.class,cascade = {CascadeType.PERSIST,CascadeType.MERGE})
   @JoinColumn(name="b_fk")
   public B getB() {
      return b;
   }

   public void setB(B b) {
      this.b = b;
   }

   @Id
   @Column(name="id", length=36)
   public String getId() {
      return id;
   }
   /**
    * @param id The id to set.
    */
   public void setId(String id) {
      this.id = id;
   }
   
   @Version
   public int getVersion() {
      return version;
   }
   
   public void setVersion(int version) {
      this.version = version;
   }
   
   public final boolean equals(Object other) {
      if(other == this)return true;
      if (other==null ||!(other instanceof A)) return false;
        A castOther = (A) other;
        return id.equals(castOther.getId());
      
   }

   @Override
   public final int hashCode() {
      
      return getId().hashCode();
   }
}


@Entity
@Table
public class B {
   protected String id;
   protected int version;
   
   public B() {
      super();
      id = java.util.UUID.randomUUID().toString();
      version = 0;
   }
   
   @Id
   @Column(name="id", length=36)
   public String getId() {
      return id;
   }

   public void setId(String id) {
      this.id = id;
   }
   
   @Version
   public int getVersion() {
      return version;
   }


   public void setVersion(int version) {
      this.version = version;
   }
   
   public final boolean equals(Object other) {
      if(other == this)return true;
      if (other==null || !(other instanceof B) ) return false;
        B castOther = (B) other;
        return id.equals(castOther.getId());
      
   }
   
   public final int hashCode() {
      
      return getId().hashCode();
   }
}

Any ideas what I am doing wrong?

Thx
Nils

nelsonhh · **Joined:** Thu Sep 08, 2005 2:14 pm **Posts:** 7

I also tried it with nullable=true

Code:

.....
   @OneToOne(targetEntity=B.class,cascade = {CascadeType.PERSIST,CascadeType.MERGE})
   @JoinColumn(name="b_fk",nullable=true,insertable=true)
   public B getB() {
      return b;
   }

.....

emmanuel · **Posted:** Fri Sep 09, 2005 6:21 am

Before checking in DB, Hibernate compare the id value with an newly instanciated object, if ids differs, then the object is considered as detached and not transiant.
Since you init the id in the constructor, Hibernate is defeated.