mapping problem and joinColumns

[nimo frey]

I want to map these two tables:

WOOD (Table)
---------------
ID_WOOD (Primary Key)
NAME

TREE (Table)
-------------
ID_WOOD (Primary Key AND Foreign Key)
ID_TREE (only Primary Key)
NAME

The Relationship: OneToMany (one Wood can consist of at least one Tree or more Trees)

My Table WOOD:

@Entity
@Table(name = "WOOD)
public class Wood implements Serializable {

private Integer idWood;
@Id
@Column(name = "ID_WOOD")
// getter/setter

private String name;
@Column(name = "NAME")
// getter/setter

//hashCode/equals
..

// relationship to TREES
private Set<Tree> trees = new HashSet<Tree>();
@OneToMany(mappedBy = "wood", targetEntity = Tree.class)
@JoinColumn(name = "ID_WOOD", referencedColumnName = "ID_WOOD", nullable = false, insertable = false, updatable = false)
// getter/setter

}

My Table TREE :

@Entity
@Table(name = "TREE )
public class Tree implements Serializable {

// Tree consists of a composite key (ID_TREE, ID_WOOD)
public static class TreeID implements Serializable
{	

@Basic(optional = false)
@Column(name = "ID_TREE", nullable = false, columnDefinition = "integer")
private Integer idApplication;
		
@Basic(optional = false)
@Column(name = "ID_WOOD", nullable = false, columnDefinition = "integer")
private Integer idDocument;

//hashCode/equals
..
}

@EmbeddedId
private TreeID treeID = new TreeID();
// getter/setter


// relationship to Wood (this does not work!!)
private Wood wood;
@ManyToOne(optional = true, targetEntity = Wood.class)
@JoinColumn(name = "ID_WOOD", referencedColumnName = "ID_WOOD", nullable = false, insertable = false, updatable = false)
// getter/setter


}

My Relationship does NOT work properly.

How would you map such a scenario?

(I have tried it also with PrimaryKeyJoinColumn, without success..I guess this is only for OneToOne-Relationships)

Any Ideas?

[nimo frey]

This HQL

"from Wood w"

returns a correct SQL:

select
  wood0_.ID_WOOD as IDWOOD _829_,
  wood0_.NAME as name_829_,
 from
  MYSCEME.WOOD wood0_

But this HQL

"from Tree t"

returns a corrupted SQL:

select
  tree0_.ID_WOOD as IDWOOD _829_,
  tree0_.ID_TREE as IDTREE _829_,
  tree0_.wood as wood3_829_,
  tree0_.NAME as name829_,
 from
  MYSCEME.TREE tree0_

This:

tree0_.wood as wood3_829_, should be a relationship (!) and has not to be in this sql-statement. So I guess, my Mapping is false! But Hibernate does not complain anything when validating the schema.

I do not know, what is wrong?

[Vijay Dharap]

nimo frey wrote:
My Table TREE :

@Entity
@Table(name = "TREE )
public class Tree implements Serializable {
// Tree consists of a composite key (ID_TREE, ID_WOOD)
public static class TreeID implements Serializable
{	
@Basic(optional = false)
@Column(name = "ID_WOOD", nullable = false, columnDefinition = "integer")
private Integer idDocument;
//hashCode/equals
..
}
@EmbeddedId
private TreeID treeID = new TreeID();
}

You would need to change the definition of idDocument to..

private Wood idDocument;

in hbm.xml

<composite-id class="Tree$TreeID" name="treeID">
	<key-property name="idApplication" column="ID_TREE"></key-property>
	<key-many-to-one name="idDocument" column="ID_WOOD" class="Wood" lazy="false"></key-many-to-one>
</composite-id>

I am not master of annotations.. So I have done this using plain old xml configuration.. You can convert above two lines into Annotated version of the same.

I see following sql formed for the hql "from Tree t"

select 
    tree0_.ID_TREE as ID1_9_, 
    tree0_.ID_WOOD as ID2_9_, 
    tree0_.NAME as NAME9_ 
    from TREE tree0_

More on this can be found in example in sample testcases from hibernate

Hope this helps.

Regards,
Vijay

[nimo frey]

thank you!

now my mapping works fine:-)

[Vijay Dharap]

nimo frey wrote:thank you!

now my mapping works fine:-)

You are quite welcome!

I also learnt a thing or two while solving your problem..

Regards,
Vijay