Why Tranferred record number and Added record number are different for Delt
We perform Initial/Delta loads to an ODS. We check the manage of this ODS and find the Tranferred record number and the Added record number are the same for Initial load, but not for Delta loads that the number of Transferred records is always greater than the number of the Added records for each Delta load. Could someone explain why?
this is because and ODS has a "key". All records loaded having the same KEY than an existing record will replace it according to your update rule of the data fields (overwrite or addition).
For the first load if there isn't any record with the same ODS key, the number of loaded records will match the number of activated records because the ODS is empty.
In all successive loads, loaded records might already exists (with the same key) in your ODS. Even within the same load, you could have two records with the same ODS key... in that case the last loaded will win (ovrwrite the provious one).
hope this clears your doubts...