Do checkout this commonly asked SAP BW HANA Interviews Q/A Series and prepare for your interviews easily. This is Part 4 of 10 Part Series.
SAP BW HANA Interview Series
1. What is the use of change log table in SAP BW?
Ans: Change log table is being used to track all the delta changes happened in the provider.
If any records got changed in the provider, by using the change log table, we can find out what has been changed, when it was changed and by whom it was changed.
Main Advantage of using change log is it very helpful in troubleshooting data related issues like if there are some incorrect entries coming or some data related loading are failing.
2. Do you know about “Record Mode” in change log?
It is basically an indicator which tells how a record is being processed in the provider. It is basically used in the delta process of data load, which shows how a data record is being updated in the target data provider.
This indicator can have 7-8 values ranging as per how the record is going to update.
- New Image (N): When a new record is being selected, then this indicator is being created.
- Reverse Image ( R): When any updation happen, the content with existing record and same key is deleted.
- Delete Image (D) : Tells that this record should be deleted.
- After Image ‘ ‘: Once the change in the record has been done, how the record looks like.
- Before Image (X): Shows what record look like before the change has been done.
- Additive Image (A) : This indicator is used when the aggregation is happening.
3. What is the Tcode of change log in SAP?
SCU3 (It contains table history) if it is a table in SAP or if its an ADSO, then change log table through manage target < utilities < change log.
4. Is there a way we can identify, if the data source supports delta mechanism or not?
In ECC, where the data source is built, Goto RSA6 or SBIW , find your datasource there and check its header settings. There in the extraction tab, check if the delta button is enabled or not.
5. What is Delta and why it is used?
When we load the data into an extractor or from extractor to BW, than during the loading of data, this feature of delta comes into existence. It refers to the changes, basically happened in the source, like which are the new records and which are the modified ones.
If we want to identify the kind of record through delta extraction, then we can check the status of this indicator in ROOSOURCE table in source.
Delta supports additive or overwrite update while loading the data from source to BW.
Hope you like the SAP BASIS Interviews Series Part 4.
Check out other parts at my website : https://acorporateguy.com/