Pass parameter from one child dataset to another child data set in BIRT report

Question

I would like to know how can we pass parameter from child dataset to another child dataset. For example I have 5 dataset in BIRT report and I am passing the parameter from main dataset to 4 dataset however for the 5th data set I would like to pass the parameter from 4th dataset instead of the main dataset. Please let me know how can we achieve it. I tried the below in open method however it didn't work.

 where joblabor.jpnum =? 
 childDataSet.setQuery(sqlText);
 childDataSet.setQueryParameterValue(1, rows[1]["jpnum"]);

Answer 1

Just change your layout struncture from this:

List/Table Main
  List/Table Child1
  List/Table Child2
  List/Table Child3
  List/Table Child4
  List/Table Child5

to this:

List/Table Main
  List/Table Child1
  List/Table Child2
  List/Table Child3
  List/Table Child4
    List/Table Child5

Note how Child5 is now a child of Child4.

Alternatively, you can do it like this:

List/Table Main
  Dynamic Text Item bound to Child4 -- hidden, sets a report variable 
  List/Table Child1
  List/Table Child2
  List/Table Child3
  List/Table Child4
  List/Table Child5 -- uses the report variable

Any way, your data model requires that the query for Child 4 will return at most one row.