Interview Questions

DWBI Interview Questions

1. What is a data-warehouse?
2. What are Data Marts?
4. What is ER Diagram?
5. What is a Star Schema?
6. What is Dimensional Modeling?
7. What Snow Flake Schema?
8. What are the Different methods of loading Dimension tables?
9. What are Aggregate tables?
10. What is the Difference between OLTP and OLAP?
11. What is ETL?
12. What are the various ETL tools in the Market?
13. What are the various Reporting tools in the Market?
14. What is Fact table?
15. What is a dimension table?
16. What is a lookup table?
17. What is a general purpose scheduling tool? Name some of them?
18. What are modeling tools available in the Market? Name some of them?
19. What is real time data-warehousing?
20. What is data mining?
21. What is Normalization? First Normal Form, Second Normal Form, Third Normal Form?
22. What is ODS?
23. What type of Indexing mechanism do we need to use for a typical data warehouse?
24. Which columns go to the fact table and which columns go the dimension table?
     (My user needs to see broken by
    
     All elements before broken = Fact Measures
     All elements after broken =    Dimension Elements
25. 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)
26. How are the Dimension tables designed?
     De-Normalized , Wide, Short , Use Surrogate Keys, Contain Additional date fields and flags.
27. What are slowly changing dimensions?
28. What are non-additive facts? (Inventory, Account balances in bank)
29. What are conformed dimensions?
30. What is VLDB? (Database is too large to back up in a time frame then it's a VLDB)
31. What are SCD1, SCD2, and SCD3?


Few More Questions if in depth

1. What are the different Dimensional modeling Techniques are Available?
2. What is the Difference between Star-schema and snow-flake-schema? When we go
for star and snow-flake?
3. What are the types of dimension and facts are in DW?
4. What is the life cycle of Data warehousing project?
5. What is a Data-model?
6. What is the Difference between Top-down Approach and Bottom-up Approach?
7. What is a factless-fact Table?
8. What is a confirmed-dimension?
9. What is a junk-dimension?
6. What is a cleansing?
11. Tell me about your current project?
12. What is your role or job profile in the project?
13. What is your Job profile?
14. What is dimesion and fact?
15. What are types of dimensions?
16. What are confirmed dimensions?
17. What are generated dimensions?
18. What are slowly changing dimensions?
19. How many data marts in your project?
20. What is data mart name in your project?
21. What is the size of your data mart?
22. What is factless fact table? Give example.
23. How many fact tables are used in the project?
24. What is your fact table name in your project?
25. How many dimension tables used in the project?
26. What are the names of the dimension tables?
27. What is Schema? Types? Explain Star-Schema and Snowflake Schema with difference.
Which schema you used in your project? Why?
28. Why star-schema called as star-schema? Give example.
29. How frequently and from where you get the data as source?
30. What is difference between data mart and data warehouse?
31. What is composite key?
32. What is surrogate key? When you will go for it?
33. What is dimensional modeling?
34. What are SCD and SGT? Difference between them? Example of SGT from your project.
35. How do you rate yourself in data warehouse?
36. What is the status of your current project?
37. What is data warehouse?
38. What is ‘Star-Schema’?
39. What is ‘Snowflake-Schema’?
40. What is difference between Star-Schema and Snowflake-Schema?
41. What is mean by surrogate key?
42. What is ‘Conformed Dimension’?
43. What is Factless Fact Table?
44. When will we use connected and unconnected lookup?
45. Which cache supports connected and unconnected lookup?
46. What is the difference between SCD Type2 and SCD Type3?
47. Draw the ETL Architecture?
48. Draw the DWH Architecture?
Example

The following script uses the DATE_FORMAT() function to display different formats. We will use the NOW() function to get the current date/time:

DATE_FORMAT(NOW(),'%b %d %Y %h:%i %p')
DATE_FORMAT(NOW(),'%m-%d-%Y')
DATE_FORMAT(NOW(),'%d %b %y')
DATE_FORMAT(NOW(),'%d %b %Y %T:%f')

The result would look something like this:


Nov 04 2008 11:45 PM
11-04-2008
04 Nov 08
04 Nov 2008 11:45:34:243

Talend Interview Questions Dear Developers, After receiving several requests we have finally decided to start writing interview questions that are generally asked in any of the Talend data integration Interview. First we have to think about what,where,when ??? What is TDI? What are the versions available? What is the difference between TDI and TDQ? What are the difference between open source and licensed tools? Talend - Merge multiple files into single file with sorting operation. Loading Fact Table Using Talend ROWNUM Analytical Function in Talend SCD-2 Implementations in Talend Deployment strategies in Talend Custom Header Footer in Talend Data Masking Using Talend How to use Shared DB Connection in Talend Load all rows from source to target except last 5 Late Arriving Dimension Using Talend Date Dimension Using Talend Dynamic Column Ordering Of Source File Using Talend what is difference between ETL and ELT components of Talend ? how to deploy talend projects ? what are types of available version of Talend ? how to implement versioning for talend jobs ? what is tMap component ? what is difference between tMap and tJoin compoents ? which component is used to sort that data ? how to perform aggregate operations/functions on data in talend ? what types of joins are supported by tMap component ?