Tuesday, 24 May 2011

Data warehousing Concepts Based Interview Questions

1. What is a data-warehouse?

2. What are Data Marts?

3. What is ER Diagram?

4. What is a Star Schema?

5. What is Dimensional Modelling?

6. What Snow Flake Schema?

7. What are the Different methods of loading Dimension tables?

8. What are Aggregate tables?

9. What is the Difference between OLTP and OLAP?

10. What is ETL?

11. What are the various ETL tools in the Market?

12. What are the various Reporting tools in the Market?

13. What is Fact table?

14. What is a dimension table?

15. What is a lookup table?

16. What is a general purpose scheduling tool? Name some of them?

17. What are modeling tools available in the Market? Name some of them?

18. What is real time data-warehousing?

19. What is data mining?

20. What is Normalization? First Normal Form, Second Normal Form , Third Normal Form?

21. What is ODS?

22. What type of Indexing mechanism do we need to use for a typical

Data warehouse?

23. Which columns go to the fact table and which columns go the dimension table? (My user needs to see <data element<data element broken by <data element<data element>

All elements before broken = Fact Measures

All elements after broken = Dimension Elements

24. What is a level of Granularity of a fact table? What does this signify?(Weekly level summarization there is no need to have Invoice Number in the fact table anymore)

25. How are the Dimension tables designed? De-Normalized, Wide, Short, Use Surrogate Keys, Contain Additional date fields and flags.

26. What are slowly changing dimensions?

27. What are non-additive facts? (Inventory,Account balances in bank)

28. What are conformed dimensions?

29. What is VLDB? (Database is too large to back up in a time frame then it's a VLDB)

30. What are SCD1, SCD2 and SCD3?

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