I have a problem in the updating children in OneToMany relationship.
The parent class P and child class C are annotated as the following:
@Entity(access=AccessType.PROPERTY)
public class Parent
{
private int id;
private int version;
private Set children = new HashSet();
@OneToMany(mappedBy="Child", fetch=FetchType.LAZY,
cascade={CascadeType.MERGE, CascadeType.REMOVE})
public Set getChildren() {return children;}
public addChild(Child c)
{
children.add(c);
c.setParent(this);
c.setParentId(this.getId());
}
public void removeChild(Child c) {children.remove(c);}
...
}
@Entity(access=AccessType.PROPERTY)
public class Child
{
private int id;
private int version;
private int parentId;
private Parent p;
@ManyToOne
@JoinColumn(name="parentId", insertable=false, updatable=false)
public JDevice getParent() {return this.p; }
public addParent(Parent p) {this.p = p; }
...
}
When users obtain an object p, remove one child c1 from p's children collection, by calling
p.removeChild(c1);
entityManager.merge(p);
Should the entity manaager automatically do a remove of the c1, ie, support persistance by reachability?
Instead, I found out that the database still has this c1 object record, and the server log did not have a trace of removing this object.
Is this a bug?
On a relevent issue: if I don't setup the CascadeType to ALL, I have to map the parentId as a separated member property, and need to set the JoinColumn annotation to updatable=false, insertable=false. This has an ugly ramification: in the parent side, when I do addChid(), I have to specifically set the parentId into the child, as shown in the code above. Is this the right way to do it? If I don't this, I always get foerign key violation exception.
-Zihong
