JPA delete a record while updating - jpa

Question

Can somebody help me with following scenario?
I have a requirement where I need to delete the membership record and child table when the child is not associated with any other parent record..else I just need to dissociate the membership record.
I'm using JPA Eclipse link...
Below are my three entities.. Please note that Parent and Child are linked via Parent_Child many-to-many relationship. I'm using Parent_Child table on both sides as we have extra columns in it..
//Parent
#Entity
#Table(name = "PARENT")
public class Parent implements java.io.Serializable {
#Id
#Column(name = "parent_id")
private String parentId;
private Set<ParentChild> parentChildSet = new HashSet<ParentChild>(0);
public String getParentId() {
return parentId;
}
public void setParentId(String parentId) {
this.parentId = parentId;
}
#OneToMany(cascade = CascadeType.ALL, fetch = FetchType.LAZY, mappedBy = "parent")
public Set<ParentChild> getParentChildSet() {
return parentChildSet;
}
public void setParentChildSet(Set<ParentChild> parentChildSet) {
this.parentChildSet = parentChildSet;
}
}
//Child
#Entity
#Table(name = "CHILD")
public class Child implements java.io.Serializable {
private String ChildId;
private Set<ParentChild> parentChildSet = new HashSet<ParentChild>(0);
#Id
#Column(name = "child_id")
public String getChildId() {
return ChildId;
}
public void setChildId(String childId) {
ChildId = childId;
}
#OneToMany(cascade = CascadeType.ALL, fetch = FetchType.LAZY, mappedBy = "child")
public Set<ParentChild> getParentChildSet() {
return parentChildSet;
}
public void setParentChildSet(Set<ParentChild> parentChildSet) {
this.parentChildSet = parentChildSet;
}
}
//Parent-Child
#Entity
#Table(name = "PARENT_CHILD")
public class ParentChild implements java.io.Serializable{
private String parentChildId;
private Parent parent;
private Child child;
#Id
#Column(name = "parent_child_id")
public String getParentChildId() {
return parentChildId;
}
public void setParentChildId(String parentChildId) {
this.parentChildId = parentChildId;
}
public Parent getParent() {
return parent;
}
public void setParent(Parent parent) {
this.parent = parent;
}
public Child getChild() {
return child;
}
public void setChild(Child child) {
this.child = child;
}
}
Relationships: Parent - Praent_Child (one-to-many)
Child - Parent_Child (one-to-many)
I'm trying it do it as below...but, it gives me integrity constraint exception as i'm deleting the child and then updating the parent
public void ParentChildServiceDAO{
........
.........
if(parentChildSet().size() > 1){
parent.getParentChildSet().remove(parentChildRecord);
child.getParentChildSet().remove(parentChildRecord);
} else{
parent.getParentChildSet().remove(parentChildRecord);
child.getParentChildSet().remove(parentChildRecord);
getJpaTemplate().remove(child);
}
update(parent);
}
Your help is greatly appreciated...