@OneToMany and composite primary keys?

by

The Manning book Java Persistence with Hibernate has an example outlining how to do this in Section 7.2. Fortunately, even if you don’t own the book, you can see a source code example of this by downloading the JPA version of the Caveat Emptor sample project (direct link here) and examining the classes Category and CategorizedItem in the auction.model package.

I’ll also summarize the key annotations below. Do let me know if it’s still a no-go.

ParentObject:

@Entity
public class ParentObject {
   @Id @GeneratedValue
   @Column(name = "parentId", nullable=false, updatable=false)
   private Long id;

   @OneToMany(mappedBy="parent", fetch=FetchType.EAGER)
   @IndexColumn(name = "pos", base=0)
   private List<ChildObject> attrs;

   public Long getId () { return id; }
   public List<ChildObject> getAttrs () { return attrs; }
}

ChildObject:

@Entity
public class ChildObject {
   @Embeddable
   public static class Pk implements Serializable {
       @Column(name = "parentId", nullable=false, updatable=false)
       private Long objectId;

       @Column(nullable=false, updatable=false)
       private String name;

       @Column(nullable=false, updatable=false)
       private int pos;
       ...
   }

   @EmbeddedId
   private Pk id;

   @ManyToOne
   @JoinColumn(name="parentId", insertable = false, updatable = false)
   @org.hibernate.annotations.ForeignKey(name = "FK_CHILD_OBJECT_PARENTID")
   private ParentObject parent;

   public Pk getId () { return id; }
   public ParentObject getParent () { return parent; }
}

More Related Contents:

  1. Hibernate throws MultipleBagFetchException – cannot simultaneously fetch multiple bags
  2. How to map a composite key with JPA and Hibernate?
  3. Hibernate Annotations – Which is better, field or property access?
  4. Do I need elements in persistence.xml?
  5. What is “the inverse side of the association” in a bidirectional JPA OneToMany/ManyToOne association?
  6. hibernate column name issues
  7. Difference Between One-to-Many, Many-to-One and Many-to-Many?
  8. Hibernate : How override an attribute from mapped super class
  9. Spring 3 MVC: one-to-many within a dynamic form (add/remove on create/update)
  10. can someone please explain me @MapsId in hibernate?
  11. JPA OneToMany and ManyToOne throw: Repeated column in mapping for entity column (should be mapped with insert=”false” update=”false”)
  12. Hibernate Annotation Placement Question
  13. hibernate composite key
  14. How to use Hibernate @Any-related annotations?
  15. Inherited abstract class with JPA (+Hibernate)
  16. org.hibernate.MappingException: Could not determine type for: java.util.Set [duplicate]
  17. Name attribute in @Entity and @Table
  18. Why should anybody put annotations on the getters or setters when using JPA to map the classes?
  19. Hibernate: Data Object with a dynamic table name by Annotations
  20. How to map one class to different tables using hibernate/jpa annotations
  21. Hibernate Issue : Foreign key must have same number of columns as referenced primary key
  22. PersistentObjectException: detached entity passed to persist thrown by JPA and Hibernate
  23. Using Hibernate’s ScrollableResults to slowly read 90 million records
  24. Hibernate criteria: Joining table without a mapped association
  25. How can I get the session object if I have the entity-manager?
  26. Using javafx.beans properties in model classes
  27. @Nullable annotation usage
  28. Hibernate could not fetch the SequenceInformation from the database
  29. spring data jpa @query and pageable
  30. How to force Hibernate to return dates as java.util.Date instead of Timestamp?

Leave a Comment