Table with DropDownBox with data from child node

Question

Hi,
I have following context:
Node Parent (0..n)
-- Node Child (0..n)
Child Attribute 1
Child Attribute 2
-- Parent Attribute 1
-- Parent Attribute 2
The parent node has a child node with cardinality 0..n. Now I created a table from the Parent node with several columns. In one column is a
DropDownBox that should display the data of the Child node, depending on the Parent node element.
Parent             |  Parent  DropDownBox           |
Parent 1                       | Parent 1 Child Attribute 1     |
Parent 1 Child Attribute 2     
Parent 2            | Parent 2 Child Attribute 1     |
Parent 2 Child Attribute 2     
How can I fill the child node with data depending on the parent node element? How is the mapping between both?
IParentElement parentElement;
IChildElement childElement;
while (rs.next()) {
   parentElement = wdContext.createParentElement();
   parentElement.setAttribute1(rs.getLong("ID"));
   parentElement.setAttribute2(rs.getString("SYSTEM"));
   wdContext.nodeParent().addElement(parentElement);
      while (rs2.next()){               
         childElement = wdContext.createChildElement();
         childElement.setAttribute1(rs2.getLong("ID"));
         childElement.setAttribute2(rs2.getString("NAME"));
         wdContext.nodeChild().addElement(childElement);
If the child node is non-singleton I have the following option
parentElement.nodeChild.addElement(childElement);
But this doesn't work for singleton nodes. How can I do something similar for singleton nodes?
Thanks for your help,
Andi

Answer 1

Not quite correct.
You can add more than one <b>element</b> to a singleton node (if cardinality is *:N).
But a singleton child node exists only once per parent <b>node </b>and not once per parent <b>element</b>.
That's an important difference.
Armin