SAP-BW BASIC INTERVIEW QUESTIONS PART 1?

What is ODS?
It is operational data store. ODS is a BW Architectural component that appears between PSA ( Persistant Staging Area ) and infocubes and that allows Bex ( Business Explorer ) reporting. It is not based on the star schema and is used primarily for details reporting, rather than for dimensional analysis. ODS objects do not aggregate data as infocubes do. Data are loaded into an IDS object by inserting new records, updating existing records, or deleting old records as specified by RECORDMODE value.   

1. How much time does it take to extract 1 million of records from an infocube?
Ans.This depends,if you have complex coding in update rules it will take longer time,orelse it will take less than 30 mins.

2. How much does it take to load (before question extract) 1 million of records to an infocube?
  Ans:

3. What are the four ASAP Methodologies?
 Project plan
Requirements gathering
Gap Analysis
Project Realization

4. How do you measure the size of infocube?
In no of records

5. Difference between infocube and ODS?
 Infocube is structured as star schema(extended) where in a fact table is surrounded by different dim table which connects to sids. And the data wise, you will have aggregated data in the cubes.
ODS is a flat structure(flat table) with no star schema concept and which will have granular data(detailed level).

6. Difference between display attributes and navigational attributes? 
 Display attribute is one which is used only for display purpose in the report.Where as navigational attribute is used for drilling down in the report.We don't need to maintain Nav attribute in the cube as a characteristic(that is the advantage) to drill down.

Q1. SOME DATA IS UPLOADED TWICE INTO INFOCUBE. HOW TO CORRECT IT?
Ans: But how is it possible?.If you load it manually twice, then you can delete it by request.

Q2. CAN U ADD A NEW FIELD AT THE ODS LEVEL? Sure you can. ODS is nothing but a table.

Q3. CAN NUMBER OF DATASOURCE HAS ONE INFOSOURCE? Yes of course. For example, for loading text and hierarchies we use different data sources but the same infosource.

Q4. BRIEF THE DATAFLOW IN BW. Data flows from transactional system to analytical system(BW). DS on the transactional system needs to be replicated on BW side and attached to infosource and update rules respectively.

Q5. CURRENCY CONVERSIONS CAN BE WRITTEN IN UPDATE RULES. WHY NOT IN TRANSFER RULES?

Q6. WHAT IS PROCEDURE TO UPDATE DATA INTO DATA TARGETS? Full and delta.

Q7. AS WE USE Sbwnn,SBiw1,sbiw2 for delta update in LIS THEN WHAT IS THE PROCEDURE IN LO-COCKPIT? No lis in lo cockpit.We will have data sources and can be maintained(append fields).Refer white paper on LO-Cokpit extractions.

Q8. SIGNIFICANCE OF ODS. It holds granular data.

Q9. WHERE THE PSA DATA IS STORED? In PSA table.

Q10.WHAT IS DATA SIZE? The volume of data one data target holds(in no.of records)

Q11. DIFFERENT TYPES OF INFOCUBES. Basic,Virtual(remote,sap remote and multi)

Q12. INFOSET QUERY. Can be made of ODSs and objects

Q13. IF THERE ARE 2 DATASOURCES HOW MANY TRANSFER STRUCTURES ARE THERE. In R/3 or in BW. 2 in R/3 and 2 in BW