Straight to it:

I have a class that is a Map. Each Task in this map can be a Sub-Task to many Tasks and have many Sub-Tasks. I am swapping over to JPA annotations for the project and am running into a little trouble making the association work. I keep getting this error from my unit tests:

Initial SessionFactory creation failed.org.hibernate.MappingException: Foreign key (FK852BA54E906BF3CF:subtasks [sub_task])) must have same number of columns as the referenced primary key (subtasks [parent_task,sub_task])

This is what I had in hbm.xml files that was working fine:

Task Configure:

<hibernate-mapping default-lazy="false">

<class name="com.tak.impl.task.TaskImpl" table="tasks">
<id name="id" column="id">
<generator class="native"/>
</id>
<property name="name"/>
<property name="startdate" type="date"/>
<property name="enddate" type="date"/>
<property name="dependant" type="boolean"/>
<property name="taskorder"/>
<property name="notes" type="text" />
<property name="type" />
<property name="ownerid" type="int" />
<property name="complete" type="boolean" />

<set name="subtasks" table="subtasks">
<key column="parent_task"/>
<many-to-many column="sub_task" class="com.tak.impl.task.TaskImpl" fetch="join"/>
</set>
</class>

</hibernate-mapping>

Sub-Task Configure:

<hibernate-mapping>

<class name="com.tak.impl.subtask.SubTaskImpl" table="subtasks">
<id name="id" column="id">
<generator class="native"/>
</id>
<property name="subTask" column="sub_task"/>
<property name="parentTask" column="parent_task"/>
</class>

</hibernate-mapping>

This is what I have now in annotations:

Task Class:

@Entity
@Table(name = "tasks")
public class TaskImpl implements Task{
//Properties
@Id @GeneratedValue
@Column(name = "id")
private int id;

public int getId()
{
return this.id;
}

< ... Lots of other getters and setters ... >

@ManyToMany(cascade = CascadeType.ALL, fetch = FetchType.EAGER, targetEntity = com.tak.impl.subtask.SubTaskImpl.class)
@JoinTable(
name = "subtasks",
joinColumns = {@JoinColumn( name = "parent_task" )},
inverseJoinColumns = {@JoinColumn( name = "sub_task" )}
)
private Set subtasks = new HashSet<Task>();

public Set getSubtasks()
{
return this.subtasks;
}

public void setSubtasks(Set subtasks)
{
this.subtasks = subtasks;
}

< ... Lots of other getters and setters ... >
}

SubTasks Class:

@Entity
@Table( name = "subtasks" )
public class SubTaskImpl{
//Properties
@Id @GeneratedValue
@Column( name = "id" )
private int id;

public void setId(int id)
{
this.id = id;
}

public int getId()
{
return this.id;
}

@Column( name = "parent_task" )
private int parentTask;

public void setParentTask(int parentTask)
{
this.parentTask = parentTask;
}

public int getParentTask()
{
return this.parentTask;
}

@Column( name = "sub_task" )
private int subTask;

public void setSubTask(int subTask)
{
this.subTask = subTask;
}

public int getSubTask()
{
return this.subTask;
}
//Constructors
public SubTaskImpl(){}

public SubTaskImpl(int id, int parentTask, int subTask)
{
this.id = id;
this.subTask = subTask;
this.parentTask = parentTask;
}
}

I summon the Gurus of Hibernate to show me the simple thing I am missing?

Thanks,

---L

Turns out it was quite simple.

My Many-To-Many Annotation was pointing to the SubTaskImpl, which is wrong, because it is returning a set of Tasks. Silly me.

It should have looked like this, for anyone who runs into this problem:

@ManyToMany(cascade = CascadeType.ALL, fetch = FetchType.EAGER, targetEntity = com.tak.impl.task.TaskImpl.class)
@JoinTable(
name = "subtasks",
joinColumns = {@JoinColumn( name = "parent_task" )},
inverseJoinColumns = {@JoinColumn( name = "sub_task" )}
)

Hi,
I'm no guru and didn't completely understand the error,
but anyway it's weird you have mapped the
to int values, they should be a reference to the entity, as a set or other collection.
I think that because of this he isn't understanding them as FKs;
you may have other problems there but maybe this is confusing things a bit;
maybe you get a better error message if you fix that.

Also as you choose ManyToMany you will need a bridge-table, so I don't think you should have FKs in the subtask table.

regards,
Sanne

nice you solved, I came too late.
Sanne