title: relation-table in dataset always returns 0 rows
body: <p>I have created a strongly typed dataset in the VS 2005 Dataset Designer. 
  There are two tables that relates to each other in a <em>one to many</em> relationship: Claim and ClaimDetail. The designer automatically creates a function GetClaimDetailRows which returns all ClaimDetailRows  for a ClaimRow. <strong>Why is this Array's length always 0?</strong>
  Because ClaimDetail contains more than 40 Million rows, i did'nt fill it before i call GetClaimDetailRows but had configured it's selectcommand that it takes a parameter idData to fill only the related records.  But that seems not to work because the  ClaimDetail-Datatable is empty. </p>
  
  <p><a href="https://i.stack.imgur.com/timPJ.jpg" rel="nofollow noreferrer"><img src="https://i.stack.imgur.com/timPJ.jpg" alt="alt text"></a><br>
  <sub>(source: <a href="http://www.bilder-hochladen.net/files/big/4709-kt.jpg" rel="nofollow noreferrer">bilder-hochladen.net</a>)</sub>  </p>
  
  <p>The automaticaly generated function in the ClaimRow-Class which returns all related ClaimDetailRows:</p>
  
  <pre><code>        Public Function GetClaimDetailRows() As ClaimDetailRow()
              If (Me.Table.ChildRelations("Claim_ClaimDetail") Is Nothing) Then
                  Return New ClaimDetailRow(-1) {}
              Else
                  Return CType(MyBase.GetChildRows(Me.Table.ChildRelations("Claim_ClaimDetail")),ClaimDetailRow())
              End If
          End Function
  </code></pre>
  
  <p>When debugging i see that it jumps into the else block but returns 0 rows.
  Do i have to fill the Claimdetail-Datatable first(ClearBeforeFill=True) for each Claim? But then i dont need to use this function anymore.</p>
  
  <p><strong>UPDATE</strong>: I now fill the Datatable(ClearBeforeFill=True)before i call the Child-function and it works. But i dont understand why it could not throw an exception(optionally) when i try to acess a child-relation without having that datatable being filled(at least with 0 rows). Instead of that it returns 0 rows what can be correct or incorrect and is difficult to detect. Is this a lack of design or am i missing something? </p>