How to map this?

[lafr]

I'm migrating an EJB 2.1 application to EJB 3.0 using JBoss 4.2.2.GA.
Some question on how to map fields and relations.
Object message contains a message header, message parts and each message part contains message lines.
message head has a generated id.
message part has a composite pk build of message head id and part_no.

@Entity
@Table(name="head")
public class Head implements Serializable
{
 @Id
 @GeneratedValue(strategy=GenerationType.IDENTITY)
 @Column(name="head_id")
 private Integer headId;

 @OneToMany(cascade=CascadeType.ALL,fetch=FetchType.LAZY)
 @OrderBy("partNo")
 @JoinColumns({
 @JoinColumn(name="head_id",referencedColumnName="head_id")
 })
 private Collection<Part> parts = new ArrayList<Part>();

This gives me an Exception saying
Repeated column in mapping for entity: Head column: head_id (should be mapped with insert="false" update="false").

Is adding 'insert="false" update="false"' to the JoinColumn properties the right way to solve this duplicate field?
What about using Transient?

I get similar problems with ManyToOne relations.
Database table for Order has a field order_type.
This field is a FK to the OrderType table id.
But order_type in combination with output_type is a composite FK to OrderProperties.
So I would have in Order.java:
- a field of type Integer named orderType
- a field of type Integer named outputType
- a ManyToOne relation to EB OrderType with JoinColumn orderType
- a ManyToOne relation to EB OrderProperties with JoinColumns orderType and outputType
So three mappings for column order_type and two mapping for column output_type.
Should I omit the plain fields in this case and mark the JoinColumn orderType for OrderProperties with 'insert="false" update="false"' then?
Or what's the best practice for something like this?

[waynebaylor]

is this a bi-directional relationship? can you post the Part entity code?

[lafr]

No, it's uni-directional.
So in the part bean I have the key-fields marked with id and so on. No hint that part is used in a relation.

@Entity
@IdClass(value=Part.PK.class)
@Table(name="part")
public class Part implements Serializable
{
 @Id
 @Column(name="msghd_serial")
 private Integer msghdSerial;

 @Id
 @Column(name="part_no")
 private Integer partNo;
 ...

[waynebaylor]

hmm, when using @OneToMany and @JoinColumn Hibernate puts the FK in the Part table...so you shouldn't have a conflict. Maybe try removing the referencedColumnName attribute and see what happens.