How to join two tables having each two fileds in common? (seems like @OneToMany with 2 joinColumns)

[Alfred Couder]

Hibernate version: 3.0.5
JBOSS Server: 4.3.0.GA
Database: Oracle10G

I am sorry to ask this question because it seems to me as some basics in SQL. Nonetheless I see nothing quite close to it in the books and web sites I am searching in.

so easy in SQL, I thought it expected it to be easy with hibernate ate well.

I have on table linked with many others. First, the DB schema is old and most of the table lacks primary keys (But embedded Id fixed that, thanks!)

Now, all I want is to make two join between table.

I basically have two table A and B. In each table, I have two common fields such as A.field1 = B.field3 and A.filed2 = B.filed4.

this a one-to-many unidirectional relation from A to B : each record from A has many related records in B.

I created an entity EA :

@Entity
@Table(name = "A)

public class EA implements Serializable {

    @Id
    @Column(name = "ID", nullable = false)
    private Integer id;

    @Column(name = "FIELD1")
    private String myField1;

    @Column(name = "FIELD2")
    private Integer myField2;

    /*  + Getters and Setters */
    
}

and another EB :

@Entity
@Table(name = "B)

public class EB implements Serializable {

    @Id
    @Column(name = "ID", nullable = false)
    private Integer id;

    @Column(name = "FILED3")
    private String myField3;

    @Column(name = "FILED4")
    private Integer myField4;

    /*  + Getters and Setters */
    
}

So how do I make my mapping so when I load an entity EA, I can have a list of all related EB? (meaning all EB respecting the joins A.field1 = B.field3 and A.filed2 = B.filed4)?

[Alfred Couder]

Thanks to parmendratyagi (on forum.hiernate.org)



This just does the job :

 

@Entity
@Table(name = "A)

public class EA implements Serializable {

    @Id
    @Column(name = "ID", nullable = false)
    private Integer id;

    @Column(name = "FILED1")
    private String field1;

    @Column(name = "FILED2")
    private Integer field2;

    /*  + Getters and Setters */

    @OneToMany
    @JoinColumns({ @JoinColumn(name = "FILED1", referencedColumnName="FILED1"),
                  @JoinColumn(name = "FILED2", referencedColumnName="FILED2")})
    private Set<EB> bList = new HashSet<EB>();
}


@Entity
@Table(name = "B)

public class EB implements Serializable {

    @Id
    @Column(name = "ID", nullable = false)
    private Integer id;

    @Column(name = "FILED1")
    private String field1;

    @Column(name = "FILED2")
    private Integer field2;

    /*  + Getters and Setters */
   
}