Procedures for implementing a snapshot scenario with custom DataSources

Question

Hi Gurus,
I have checked the How To paper ([How to Handle Inventory Management Scenarios in BW (NW2004)|http://www.sdn.sap.com/irj/scn/index?rid=/library/uuid/f83be790-0201-0010-4fb0-98bd7c01e328]). However, only SAP standard BW objects are mentioned in the paper e.g. InfoCube (0IC_C03), Material Stock InfoSource (2LIS_03_BX), Material movements IS (2LIS_03_BF) and Revaluations IS (0LIS_03_UM).
On the contrary, I need to handle custom DataSources for the Snapshot scenario. Are there any differences in the implementation methodology? Which additional aspects should I take into consideration? For example, the load sequence, delta type, etc.
Could you please list out the step-by-step procedures for such an implementation?
Thanks in advance!
Regards,
Meng

Answer 1

Hi Meng,
You can approach this in two ways.
1) If the volume of data is not much, you can derive the balance at query level, as follows.
User enters the date, based on this restrict your key figure to display all values less than this date.
2) If the volume of data is high, then you will have issues with performance if you are calculating the balance in the front end. In this case, you can model this with 'Non cumulative' key figure.  Again there are 2 ways of approaching this back end solution based on the volume of data. ( Say in one case you have 2 years of history in your DSO and in the second case, you have  5 years of history ).
A) For example, If there are only 2 years of history
Create a non cumulative Key figure 'ZBALANCE' with inflow and outflow, in a cube.
Map this to your credit and debit as + and - respectively and map the calender day to posting date.
Just initialise the dataload with data transfer and start loading the delta as normal.
You will be able to see the balances for each and every calday in your reporting.
This approach is straight forward and simple.
Compress the cube for getting the better performance.
B) If there are 5 years of history and you are not interested in loading all the 5 years data in getting the balance
Here you want to have the initial balance, continue delta and would like to load 2 years of history.
The cube and non cumulative KF are created as mentioned above.
For generating initial balance, you have to create another DSO without calander day and ZBalance mapped to credits and debits in additive mode. Load your DSO data into this new DSO to generate initial balance. This balance will be loaded to your cube as initial balance. ( Like 2LIS_03_BX ).
You have to compress this request with marker update ( Must ).
Load your historical data for 2 years from the original DSO. Compress without marker update ( Must ).
initialise without data transfer from DSO to cube and load deltas normally.
Compress the delta requests normally for performance reasons.
Please read the 'Inventory document' in detail.
Please let me know, if any of the information is still not clear.
Thanks,
Krishnan