I want to know how does a DSO manages its Delta.
The exact points.
DSO has three tables i) Activation Queue/ New Table ii) Active table and iii) Change Log table.
DSO uses Change Log table to Manage Delta Records.
In DSO you can set whether Key Figures should get Overwrite/Summation based on Key Fields.
Now Lets take an example where today we got one sales order with quantity 50
When it gets loaded to the DSO and activated, we will get the below records in Active Table and Change Log table(there will be no data in Activation Queue/New Table upon activation)
Chage Log Table
111 50 N(orecordmode - New Image)
when this record loaded to the cube, it will be as below(Info Cube is always Additive)
As this record is loaded to the CUBE, Delta Time stamp for this source and target will get update in ROOSPRMSC table with all the details.
Now tomorrow we got same sales order with quantity 70. So this record has to get change in DSO and CUBE. As DSO is overwrite new value will get overwrite in place of old value, so that we will get correct value.
What about CUBE? Cube is always additive so if I load this new record to CUBE then the quantity will become 120 which is wrong.
This is the place where orecordmode comes into picture. It maintains the images for changed and new records so that records will correctly uploaded to the cube.
Now as the quanity is changed to 70, we will get below records in active and change log table of DSO upon activation.
Change Log Table
111 -50(X -- Before Image)
111 70( ' ' -- After Image) symbol for after image is 'Space'
So if we load this record to the target as a delta the above two records from change log table will get loaded to the CUBE.
Now what happens
111 50 (already Existing)
111 70 (Which is expected)
Hope this gives you clear idea..
You can refer my document for all the details on 0recordmode
DSO are overwrite update type. Mainly they support these delta of type
ABR: After before and Reverse image
AIE/AIM: After image
ADD: Additive image (if update type is set to additive)
For better understanding about these delta type refer this document...