SAP BW/BI Interview Questions Part-1

1. What are the extractor types?

Ans: There are three types of extractors

 Application Specific - BW Content FI, HR, CO, SAP CRM, LO Cockpit
Customer-Generated Extractors  - FI-SL, CO-PA
Cross Application - Generic Extractors based on Table, View, InfoSet, Function Module

2. What are the steps involved in LO Extraction?

 Ans: The steps are

a)      RSA5 Select the DataSources
b)      LBWE Maintain DataSources and Activate Extract Structures
c)      LBWG Delete Setup Tables
d)      0LI*BW Setup tables
e)      RSA3 Check extraction and the data in Setup tables
f)       LBWQ Check the extraction queue
g)      LBWF Log for LO Extract Structures
h)     RSA7 BW Delta Queue Monitor

3. What is the difference between ODS, InfoCube and MultiProvider?

Ans:

a)      ODS: Provides granular data, allows overwrite and data is in transparent tables and provides operational reports.
b)      CUBE: Follows the star schema, we can only append data i.e. additive property and provides analytical reports.
c)      MultiProvider: It is the logical unification of physical infoproviders. It does not have physical data. There should be one characteristic in common for unifying the physical infoproviders.

4. What are Start routines, Transfer routines and Update routines? 

Ans:

Start Routines: The start routine is run for each DataPackage after the data has been written to the PSA and before the transfer rules have been executed. It allows complex computations for a key figure or a characteristic. It has no return value. Its purpose is to execute preliminary calculations and to store them in global DataStructures. This structure or table can be accessed in the other routines. The entire DataPackage in the transfer structure format is used as a parameter for the routine.

 Transfer / Update Routines: They are defined at the InfoObject level. It is like the Start Routine. It is independent of the DataSource. We can use this to define Global Data and Global Checks.

5. What is the table that is used in start routines?

Ans: Always the table structure will be the structure of an ODS or InfoCube. For example if it is an ODS then active table structure will be the table.

6. Explain how you used Start routines in your project?

Ans: Start routines are used for mass processing of records. In start routine all the records of

DataPackage is available for processing. So we can process all these records together in start routine.

In one of scenario, we wanted to apply size % to the forecast data. For example if material M1 is forecasted to say 100 in May. Then after applying size %(Small 20%, Medium 40%, Large 20%, Extra Large 20%), we wanted to have 4 records against one single record that is coming in the info package. This is achieved in start routine.

7. What are Return Tables?

Ans: When we want to return multiple records, instead of single value, we use the return table in the Update Routine. Example: If we have total telephone expense for a Cost Center, using a return table we can get expense per employee.

8. What is compression? 

Ans: When we perform the compression the data in the infocube moves from F-Fact table to the E-Fact table. The entire request IDs will be deleted and compressed into a single request. When you perform this compression by choosing the check box “with zero elimination” keyfigures with the zero values also will be deleted. As a whole compression saves database size and increases the query performance.

9. What is Rollup? 

Ans: This is used to load new requests (delta records) in the Infocube into the aggregates. If we have not performed a rollup then the current data (which is not rolled up) will not be available for reporting

10. What is table partitioning and what are the benefits of partitioning in an Infocube?

Ans: It is the method of dividing the fact table which would improve the query performance. We can perform partition only when we have either 0CALMONTH or 0FISCPER in the infocube. When we perform partition the E fact table of the infocube will be partitioned and hence we should perform the compression followed by partition in order to get the partition effect. Partitioning helps to run the report faster as data is stored in the relevant partitions.

11. What are the options available in transfer rules for mapping?

Ans: InfoObject, Constant, Routine, Formula

12. How would you optimize the dimensions? 

Ans: We should define as many dimensions as possible and we have to take care that no single dimension crosses more than 20% of the fact table size. If the dimension table crosses more than 20% of the size of the fact table, we should declare the dimension as line item dimension (There should not be more than one characteristic assigned to a dimension in order to declare it as line item dimension)

13. How to find the size of the dimension table?

Ans: With the program SAP_CUBES_DESIGN

14. What are Conversion Routines for units and currencies in the update rule?

Ans: Using this option we can write ABAP code for Units / Currencies conversion. If we enable this flag then unit of Key Figure appears in the ABAP code as an additional parameter. For example, we can convert units in Pounds to Kilos.

15. Can an InfoObject be an InfoProvider, how and why? 

Ans: Yes, when we want to report on Characteristics or Master Data. We have to right click on the InfoArea and select "Insert characteristic as data target". For example, we can make 0CUSTOMER as an InfoProvider and report on it.

16. What is Open Hub Service?

Ans: The Open Hub Service (process) enables us to distribute data from an SAP BW system into external system. In BW 3.5 version an object called Infospoke is used to send data from BW to the external systems. In BI 7 version we use open hub destination (object) for this purpose.

17. What is BW Statistics and what is its use? 

Ans: They are group of Business Content InfoCubes which are used to measure performance for Query and Load Monitoring. It also shows the usage of aggregates, OLAP and Warehouse management. There are some standard reports on these infocubes which provides us the in information about the BW system performance as a whole.

18. What are the delta options available when you load from flat file? 

Ans: The 3 options for Delta Management with Flat Files:

Full Upload

New Status for Changed records (ODS Object only)

Additive Delta (ODS Object & InfoCube

19. Can we make a datasource to support delta?

Ans: If this is a custom (user-defined) datasource you can make the datasource delta enabled. While creating datasource from RSO2, after entering datasource name and pressing create, in the next screen there is one button at the top, which says generic delta. Generic delta can be enabled based-

a)      Time stamp
b)      Calendar day
c)      Numeric pointer, such as document number & counter

20. How much time does it take to extract 1 million (10 lakhs) of records into an infocube?

Ans: This depends, if you have complex coding in update rules it will take longer time, or else it will take less than 30 minutes.

21. What is ASAP Methodologies?

Ans: ASAP stands for Accelerated SAP methodology which is used to implement and deliver the project efficiently.

The five stages of ASAP methodologies are- 

Project plan, Business Blue print, Realization, Final preparation & Go-Live - support. 

1. Project Preparation: In this phase the system landscape will be set up.

2. Business Blueprint: It is a detailed documentation of your company's requirements. (I.e. what are the objects we need to develop are modified depending on the client's requirements).

3. Realization: In this only, the implementation of the project takes place (development of objects etc)

And we are involved in the project from here only.

4. Final Preparation: Final preparation before going live i.e. testing, conducting pre-go-live, end user training etc.

End user training is given that is in the client site you train them how to work with the new environment, as they are new to the technology.

5. Go-Live & support: The project has gone live and it is into production. The Project team will be supporting the end users.

21. Difference between display attributes and navigational attributes?

Ans: Display attribute is one, which is used only for display purpose in the report. Whereas navigational attribute is used for drilling down in the report. We don't need to maintain Navigational attribute in the cube as a characteristic (that is the advantage) to drill down.

22. Some data is uploaded twice into infocube. How to correct it?

Ans: Selective deletion if the data is already compressed otherwise deletes the duplicate request

23. Can number of Datasources have one infosource?

Ans: Yes of course. For example, for loading text and hierarchies we use different data sources but the same Infosource which is already used for attribute

24: Can many infosources assign to one infoprovider?

Ans: Yes

25: Can many transaction Datasources can be assigned to one infosource?

Ans: No, it’s a one to one assignment in this case.

26. Currency conversions can be written in update rules. Why not in transfer rules?

Ans:

27: What are the types of data update we have in BW?

Ans: Full, Initialize delta (init), Delta, Repair full

28: What is early delta?

Ans:

29. When do we go for initialization without data transfer?

Ans:

30. Why we delete the setup tables (LBWG) & fill them (OLI*BW)?

Ans: For the first time when we are loading the historical data in the setup tables as a caution we perform deletion for the setup tables in order to avoid any junk data residing in it. Also when a DataSource is enhanced we will go for deleting the setup tables followed by the statistical setup (filling setup tables)

31. Why do we have set up tables in LO extraction only but not the other extractions?

Ans: As the historical data volume in case of logistics modules (SD, MM, and PP) is high we have setup table which are the intermediate tables of type transparent tables.

31) What Are The Different Variables Used In BEx?

Ans: Different Variable's are Texts, Formulas, Hierarchies, Hierarchy nodes & Characteristic values.

32) What is processing type of a variable?

Ans: The way how the variable gets the input value is called processing type.

We have the following five processing types-

Variable Types are:

a)      Manual entry /default value
b)      Replacement path
c)      SAP exit
d)      Customer exit
e)      Authorization

33) How many Levels we can go In Reporting?

Ans: We can drill down to any level by using Navigational attributes and jump targets (RRI).

34) What are Indexes?

Ans: Indexes are data base indexes, which help in retrieving data faster.

35) What is the significance of KPI's?

Ans: KPI’s (Key Performance indicators) indicate the performance of a company. These are key figures

36) What types of partitioning are there for BW?

Ans: There are two Partitioning Performance aspects for BW (Cube & PSA)

37) How can I compare data in R/3 with data in a BW Cube after the daily delta loads? Are there any standard procedures for checking them or matching the number of records?

Ans: You can go to R/3 T-Code RSA3 and run the extractor. It will give you the number of records extracted. Then go to BW Monitor to check the number of records in the PSA and check to see if it is the same & also in the monitor header tab.

38) What is the difference between writing a routine in transfer rules and writing a routine in update rules?

Ans:  If you are using the same Infosource to update data in more than one data target its better u write in transfer rules because u can assign one InfoSource to more than one data target & and whatever logic we write in update rules it is specific to particular one data target.

39) Can one infosource send data to multiple datatargets?

Ans:Yes

40) What does the number in the 'Total' column in Transaction RSA7 mean?

Ans: The 'Total' column displays the number of LUWs that were written in the delta queue and that have not yet been confirmed. The number includes the LUWs of the last delta request (for repetition of a delta request) and the LUWs for the next delta request. A LUW only disappears from the RSA7 display when it has been transferred to the BW System and a new delta request has been received from the BW System.