Adding associations to a join entity..

[Eric Nielsen]

I'm running into some errors when trying to hang supplementary associations off of a join entity.

Competition----1:M----StudioCompetition-----M:1----- Affiliation
                                   |
                                   |
                                 1:M
                                   |
                          StudioSessionPrice

Ie StudioCompetition is a join entity that replaces a direct M:M between Affiliation and Competition that provides a place to hang additional qualifies of the association.

I can't seem to figure out how to allow hook up the extra associations -- I get errors regarding the number of columns in the foreign key.

My current setup looks like:

@Entity
@Table(name="competition")
public class Competition {
@Id @GeneratedValue(strategy=GenerationType.IDENTITY)
private Long id;
 
@OneToMany(mappedBy="competition",
cascade={CascadeType.PERSIST,CascadeType.MERGE,CascadeType.REMOVE})
@org.hibernate.annotations.Cascade(value=org.hibernate.annotations.CascadeType.SAVE_UPDATE)
private List<StudioCompetition> affiliationsAttending = new ArrayList<StudioCompetition>();
}
 
@Entity
public class Affiliation {
@Id @GeneratedValue(strategy=GenerationType.IDENTITY)
private Long id;
    
@OneToMany(mappedBy="competition",
cascade={CascadeType.PERSIST,CascadeType.MERGE,CascadeType.REMOVE})
@org.hibernate.annotations.Cascade(value=org.hibernate.annotations.CascadeType.SAVE_UPDATE)
private List<StudioCompetition> attendedCompetitions = new ArrayList<StudioCompetition>();
 
}
 
@Entity
public class StudioCompetition {
@SuppressWarnings("serial")
@Embeddable
public static class Id implements Serializable {
private final Long affiliation_id;
private final Long competition_id;
public Id() {
affiliation_id=null;
    competition_id=null;
}
public Id(Long affilId, Long competitionId) {
this.affiliation_id=affilId;
this.competition_id=competitionId;
}
public boolean equals (final Object o) {
if (o instanceof Id) {
final Id that = (Id)o;
return this.affiliation_id.equals(that.affiliation_id) &&
   this.competition_id.equals(that.competition_id);

} else {
return false;
}
}
public int hashCode() {
return affiliation_id.hashCode()+competition_id.hashCode();
}
}

@SuppressWarnings("unused")
@EmbeddedId
private Id id=new Id();

@ManyToOne(cascade={CascadeType.PERSIST,CascadeType.MERGE,CascadeType.REFRESH})
@Cascade({org.hibernate.annotations.CascadeType.SAVE_UPDATE})
@JoinColumn(nullable=false, insertable=false, updatable=false)
private Affiliation affiliation;
 
@ManyToOne(cascade={CascadeType.PERSIST,CascadeType.MERGE,CascadeType.REFRESH})
@Cascade({org.hibernate.annotations.CascadeType.SAVE_UPDATE})
@JoinColumn(nullable=false,insertable=false, updatable=false)
private Competition competition;
 
@OneToMany(mappedBy="affiliation",
cascade={CascadeType.PERSIST,CascadeType.MERGE,CascadeType.REMOVE})
@org.hibernate.annotations.Cascade(value=org.hibernate.annotations.CascadeType.SAVE_UPDATE)
private List<StudioSessionPrice> sessionPrices = new ArrayList<StudioSessionPrice>();
}
 
@Entity
public class StudioSessionPrice {
@Id @GeneratedValue(strategy=GenerationType.IDENTITY)
private Long id;

@ManyToOne(cascade={CascadeType.PERSIST,CascadeType.MERGE,CascadeType.REFRESH})
@Cascade({org.hibernate.annotations.CascadeType.SAVE_UPDATE})
@JoinColumn(nullable=false,insertable=false, updatable=false)
private StudioCompetition studioComp;
 
}

which yields an error like:

Caused by: org.hibernate.AnnotationException: A Foreign key refering com.ballroomregistrar.compinabox.online.data.StudioCompetition from com.ballroomregistrar.compinabox.online.data.StudioSessionPrice has the wrong number of column. should be 2
at org.hibernate.cfg.annotations.TableBinder.bindFk(TableBinder.java:276)
at org.hibernate.cfg.FkSecondPass.doSecondPass(FkSecondPass.java:64)
at org.hibernate.cfg.AnnotationConfiguration.processFkSecondPassInOrder(AnnotationConfiguration.java:474)

Earlier I had the association on the StudioSessionPrice named "affiliation" of Type Affiliation... so it wasn't really bi-directional (more of a loop). Which fails with a similar error message -- different wording, but same general intent -- wrong number of columns.. That error made sense since I had the mapped by of something with a two column PK mapped by a single column/wrong type. So I switched to the code shown above.

Is there a way to back the supplementary association work? Or do I need to lose the compound primary key, add an artificial key to the join table and just treat it like a regular entity?
[ December 25, 2008: Message edited by: Eric Nielsen ]