Annotations and Composite primary keys question

athu9999 · **Joined:** Mon Mar 28, 2005 12:58 pm **Posts:** 27

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Hibernate version: 3.0 w/ annotations 3.0 beta1

Mapping documents:

Code between sessionFactory.openSession() and session.close():

Full stack trace of any exception that occurs:

Name and version of the database you are using: Hypersonic SQL

The generated SQL (show_sql=true):

Debug level Hibernate log excerpt:

I'm trying to implement a relation table with a composite primary key. This table is supposed to associate to entity tables, TableA and TableB :

Code:

@Entity
public class TableA
{
    private Long aId;
    private Set<RelationTable> relationList = new HashSet<RelationTable>();

    ....
    @OneToMany
    @JoinColumn(name  = "a_id")
    public Set<RelationTable> getRelationList()
    {
        return relationList;
    }
    ....
}

@Entity
public class TableB
{
    private Long bId;
    ....
}

This is the relation table for "connecting" Table A and TableB. It has a composite primary key.:

Code:

@Entity
public class RelationTable
{
    private RelationTablePk relationTableId;

    public RelationTable()
    {
    }

    @Id(generate = GeneratorType.NONE)
    public RelationTablePk getRelationTableId()
    {
        return relationTableId;
    }

    public void setRelationTableId(final RelationTablePk id)
    {
        this.relationTableId= id;
    }
}

This is the primary key class for the above relation table:

Code:

@Embeddable
public class RelationTablePk implements Serializable
{
    private TableA tableA;
    private TableB tableB;

    public RelationTablePk ()
    {
    }

    @JoinColumn(name  = "a_id")
    public TableA getTableA()
    {
        return tableA;
    }

    public void setTableA(final TableA a)
    {
        this.tableA= a;
    }

    @JoinColumn(name = "b_id")
    public TableB getTableB()
    {
        return tableB;
    }

    public void setTableB(final TableB b)
    {
        this.tableB = b;
    }

The above relationship mapping between the RelationTable and the RelationTablePk is working fine. The problem I have is in TableA where I want to get a list of all the RelationTables it is associated with. When I try to get the size of the list in my test class, I get the following exception:

Code:

org.hibernate.exception.GenericJDBCException: could not initialize a collection: 

At this point, I want to make sure what I'm trying to do is using the right annotations. Any input would be appreciated.

emmanuel · **Posted:** Tue Apr 12, 2005 5:56 am

I don't get your use case.
Why don't you use a many to many between A and B using RelationTable as the association table?

Code:

public class A {
  @ManyToMany
  @AssociationTable(table=@Table(name="RelationTable"), ...)
  Set<B> getBs() {

athu9999 · **Joined:** Mon Mar 28, 2005 12:58 pm **Posts:** 27

Yup. I ended up doing that. :) Thanks for the reply though!

rleibman · **Joined:** Wed Apr 05, 2006 4:33 pm **Posts:** 5

What I don't get is what to do when the RelationTable has some data of its own that's important (in my case, you have a recipe, an ingredient and the RelationTable is ingredient_quantity, with an extra double value).
How do you map *that*?

emmanuel · **Posted:** Sun Apr 16, 2006 7:12 pm

through an intermediate entity