Is it possible to define default object inside a SET element in HBM?

lets say I have mapping of a set within Parent hbm file:

    <set cascade="all" inverse="true" lazy="false" name="chil开发者_运维问答dren">
       <key column="parentChildId" foreign-key="fk_fk" not-null="true" on-   
         delete="cascade"/>
     <one-to-many class="Child" not-found="ignore"/>
   </set> 

Is it anyhow possible to define in Parent hbm a default child, that when ever parent is created, one child is added inside of this set????

I know it sounds weird, but because of some performance issue i must try to create as least calls to server (here one was saving parent and other call was saving default child).

I appreciate all the help.

Thank you

---

What do you mean by "server"? Do you mean the database server? If so, then there's no way to create a parent and a child in one SQL statement. But Hibernate uses batch updates, so it should be very efficient.

If you mean the "application server", then it sounds like a functional problem, not a technical one. Change your parent creation method to make it create a child at the same time. You could even do that using a factory method in the Parent class :

public class Parent {
    public static Parent createParentWithDefaultChild() {
        Parent p = new Parent();
        p.addChild(new Child());
        return p;
    }
    // ...
}