Disposing data table? - vb.net

Question

I was reading this msdn article today and I am curious about finally part with disposing datatable. Is that really necessary? why should we dispose a datatable? If I exit the function or sub, is it not releasing the resources?
Explanation in the article is;
Dispose of the temporary data tables to release the resources.
Private Sub UpdateDB()
Dim deletedChildRecords As NorthwindDataSet.OrdersDataTable = _
CType(NorthwindDataSet.Orders.GetChanges(Data.DataRowState.Deleted), NorthwindDataSet.OrdersDataTable)
Dim newChildRecords As NorthwindDataSet.OrdersDataTable = _
CType(NorthwindDataSet.Orders.GetChanges(Data.DataRowState.Added), NorthwindDataSet.OrdersDataTable)
Dim modifiedChildRecords As NorthwindDataSet.OrdersDataTable = _
CType(NorthwindDataSet.Orders.GetChanges(Data.DataRowState.Modified), NorthwindDataSet.OrdersDataTable)
Try
If deletedChildRecords IsNot Nothing Then
OrdersTableAdapter.Update(deletedChildRecords)
End If
CustomersTableAdapter.Update(NorthwindDataSet.Customers)
If newChildRecords IsNot Nothing Then
OrdersTableAdapter.Update(newChildRecords)
End If
If modifiedChildRecords IsNot Nothing Then
OrdersTableAdapter.Update(modifiedChildRecords)
End If
NorthwindDataSet.AcceptChanges()
Catch ex As Exception
MessageBox.Show("An error occurred during the update process")
' Add code to handle error here.
Finally
If deletedChildRecords IsNot Nothing Then
deletedChildRecords.Dispose()
End If
If newChildRecords IsNot Nothing Then
newChildRecords.Dispose()
End If
If modifiedChildRecords IsNot Nothing Then
modifiedChildRecords.Dispose()
End If
End Try
End Sub

Answer 1

To answer your question, is it necessary to dispose a datatable? The concensus is no, here's my thought.
Setting things to null or nothing doesn't remove the memory used by the instance of the object. Neither does dispose. The GC does, when it runs. Remember, when you have a reference variable, you have a pointer to an object. When you repoint that variable to a null address, it doesn't delete the data at the previous address, nor does it free the memory.
Basically, dispose is useful for preparing your objects for being destroyed, but it doesn't actually release the memory used by the object. If you're dealing with resources that need cleaning up, like open streams, database connections, things like that, dispose is great.