How to save only subclass related data in Hibernate

Question

I have the following classes

Concrete class Item

@Entity
@Table(name = "ITEM")
@Inheritance(strategy= InheritanceType.JOINED)
Class Item implements Serializable {        
  private static final long serialVersionUID = 1L;
  @Id
  @Column(name = "NAME")
  private final String name;
  @Column(name = "PRICE")
  private BigDecimal price;
}

Concrete class AddedItem that extends Item

@Entity
@Table(name = "ADDED_ITEM")
@PrimaryKeyJoinColumn(name = "NAME")
public class AddedItem extends Item {
   @Column(name = "TOTAL_PRICE")
   private BigDecimal totalPrice;
   @Column(name = "QUANTITY")
   private Integer quantity;
   @ManyToOne
   @JoinColumn(name = "INVOICE_ID")
   private Invoice invoice;
 }

The Invoice class that has a one to many mapping with AddedItem

@Entity
@Table(name = "INVOICE"
public class Invoice implements Serializable {

  @Id
  @GeneratedValue(strategy = GenerationType.AUTO)
  @Column(name = "INVOICE_ID")
  private Long billNo;
  @Column(name = "BILLDATE")
  @Temporal(TemporalType.TIMESTAMP)
  private Date billDate;
  @Column(name = "CUSTOMERNAME")
  private String customerName;
  @OneToMany(fetch = FetchType.LAZY, mappedBy = "invoice", cascade = CascadeType.ALL)
  private final List<AddedItem> itemsAdded;
}

When I try to save an Invoice instance I am getting the following exception:

org.hibernate.util.JDBCExceptionReporter logExceptions
SEVERE: ORA-00001: unique constraint (ITEM_PK) violated

org.hibernate.event.def.AbstractFlushingEventListener performExecutions
SEVERE: Could not synchronize database state with session
org.hibernate.exception.ConstraintViolationException: Could not execute JDBC batch      update
...

How can I tell Hibernate to store only the subclass information as I prefetch the Item related information?

score 0 · Answer 1 · edited May 23 '17 at 12:13

In @Inheritance(strategy= InheritanceType.JOINED) you have to define a @DiscriminatorColumn to determine the class of the row. Adding this should resolve the problem. If you are using Hibernate 3.1 or lower (hopefully you're not), @DiscriminatorFormula should do the job, but I never really tried it personally.

Next on your AddedItem entity, the @PrimaryKeyJoinColumn(name = "NAME") (javadoc, stackoverflow is pretty much just for show, but it should not cause any harm.

If AddedItem is public, so should Item entity be.

edit: Since your ID field is a String, are you sure you are using correct unique values for it?

How to save only subclass related data in Hibernate

1 Answers1