First stage (between StorageChangeBegin and StorageChanged) is for modifying the ADO.NET data set StorageDataSet by any means available in ADO.NET. Simple tables are filled with rows or modified at this stage.
Second stage (between StorageChanged and StorageChangeEnd) is for synchronizing the C1DataSet with changed underlying data. Table views are filled with rows on this stage, using the SetTableViewRows method.
StorageChanged call is required between StorageChangeBegin and StorageChangeEnd, to mark the end of the first stage and the beginning of the second.
Calling StorageChanged with clearTableViews=False allows to make simple changes to StorageDataSet without modifying table view rows. For example, you might want to change some field values in the underlying ADO.NET data set, and you are sure that this will not affect table view rows in any way, that is, all table view rows will still point to the same table rows, only data in the table rows will change. In such case, you can use clearTableViews=False and skip the second stage (synchronization). But this must be done with caution, because C1DataObjects does not verify these conditions. If, for example, you delete a table row that was pointed to by a table view row, it will cause unpredictable behavior. Also, using clearTableViews=False means that the collection of table view rows will not change, so any rows added to the ADO.NET data set will not be reflected in the table views.