JPA : many-to-many - only one foreign key in the association table
- by Julien
Hi,
I mapped two classes in a ManyToMany association with these annotations :
@Entity
@Inheritance(strategy=InheritanceType.TABLE_PER_CLASS)
public abstract class TechnicalItem extends GenericBusinessObject implements Resumable{
@SequenceGenerator(name="TECHNICAL_ITEM_ID_GEN", sequenceName="TECHNICAL_ITEM_ID_SEQ")
@Id
@Column(name = "\"ID\"", nullable = false)
@GeneratedValue(strategy = GenerationType.SEQUENCE, generator = "TECHNICAL_ITEM_ID_GEN")
private int id;
@ManyToMany(mappedBy = "referencePerformanceItems", fetch=FetchType.LAZY)
private List testingRates;
}
@Entity
@DiscriminatorValue("T")
public class TestingRate extends Rate {
@ManyToMany(fetch=FetchType.LAZY)
@JoinTable(name="ecc.\"TESTING_RATE_TECHNICAL_ITEM\"",
joinColumns = {@JoinColumn(name = "\"TESTING_RATE_ID\"")},
inverseJoinColumns = {@JoinColumn(name = "\"TECHNICAL_ITEM_ID\"")})
//@ManyToMany(mappedBy = "testingRates", fetch=FetchType.LAZY)
private List referencePerformanceItems;
}
The sql generated for the association table creation is :
create table ecc."TESTING_RATE_TECHNICAL_ITEM" (
"TESTING_RATE_ID" int4 not null,
"TECHNICAL_ITEM_ID" int4 not null
);
alter table ecc."TESTING_RATE_TECHNICAL_ITEM"
add constraint FKC5D64DF6A2FE2698
foreign key ("TESTING_RATE_ID")
references ecc."RATE";
There is no mention of the second foreign key "TECHNICAL_ITEM_ID" (the second part of the composite foreign key which should be in the association table).
Is it a normal behaviour ?
What should I do in the mapping if I want my 2 columns are 2 foreign keys referencing the primary keys of my 2 concerned tables.
I use a PostGreSQL database and Hibernate as JPA provider.
Thanks,
Julien
