Skip to main content

Top 160 Datawarehouse Interview Question


Hi Guys,

Me and some of my friends attended interview in Accenture,Wipro,TCS,Sapinet,zensar technologies, Seventh Sense Technologies for Datawarehouse architect . 

I have listed out the Datawarehouse Interview question below.


What is datawarehouse 

What is schema, explain all types of schema 

explain star schema 

explain snow flake schema 

What is facts? Types of facts 

type of fact table 

Difference between snow and star 

GRAIN AND GRANUARITY 

datawarehouse ARCHITECTURE 

explain dimensional, breif all types of dimension 

What is Meta data? 

Briefly state different between data ware house & data mart? 

What is galaxy schema? 

what is scd, explain all types of scd 

After we create a SCD table, can we use that particular Dimension as a dimension table for Star Schema? 

What is Core Dimension? 

How much data hold in one universe. 

Can any one explain about Core Dimension, Balanced Dimension, and Dirty Dimension? 

Can any one explain the Hierarchies level Data warehousing. 

What is data cleaning? How can we do that? 

What is dimension modeling? 

Where the cache files stored? 

How can you import tables from a database? 

What is drilling across? 

How Many different schemas or DW Models can be used in Siebel Analytics. I know Only 
STAR and SNOW FLAKE and any other model that can be used? 

What is loop in Data warehousing? 

How many clustered indexes can u create for a table in DWH? In case of truncate and delete command what happens to table, which has unique id. 

What is hybrid slowly changing dimension? 

Can a dimension table contain numeric values? 

How do you create Surrogate Key using Ab Initio? 

What is the difference between star and snowflake schemas? 

What is a CUBE in data warehousing concept? 

What is the difference between Snowflake and Star Schema? What are situations where Snowflake Schema is better than Star Schema when the opposite is true? 

What is ER Diagram? 
What is degenerate dimension table? 

What is VLDB? 

What is Dimensional Modeling? 

What are the possible data marts in Retail sales? 

What is meant by metadata in context of a Data warehouse and how it is important? 
What is a linked cube? 

What is surrogate key? Where we use it? Explain with examples.
 
What are data validation strategies for data mart validation after loading process 
What is Data warehousing Hierarchy? 

What is BUS Schema? 

What are the methodologies of Data Warehousing? 

What is conformed fact? 

What is Difference between E-R Modeling and Dimensional Modeling? 

Why fact table is in normal form? 

What is junk dimension? What is the difference between junk dimension and degenerated dimension? 

What is the main difference between Inmon and Kimball philosophies of data warehousing? 

What is the difference between view and materialized view
 
What is the advantages data mining over traditional approaches? 

What are the benefits of data warehousing? 

What is OLAP? 

What is OLTP? 

What are measures? 

What are aggregations? 

What are cubes? 

What is the PivotTable® Service? 

What are offline OLAP cubes? 

What are virtual cubes? 

What are MOLAP cubes? 

What are ROLAP cubes? 

What are HOLAP cubes? 

What is the approximate size of a data warehouse? 

What are the steps to build the data warehouse? 

What is the data type of the surrogate key? 

What are the different types of data warehousing? 

What is the data type of the surrogate key? 

What are the differences between star and snowflake schema? 

What is Log Switch? 

What is On-line Redo Log? 
Which parameter specified in the DEFAULT STORAGE clause of CREATE TABLESPACE cannot be altered after creating the table space? 

What are the steps involved in Database Startup? 

What are the steps involved in Instance Recovery? 

Can Full Backup be performed when the database is open? 

What are the different modes of mounting a Database with the Parallel Server? 

Explain the relationship among Database, Table space and Data file? 

What is the difference between OLAP and OLTP? 

What is the difference between aggregate table and materialized view? 

"A dimension table is wide but the fact table is deep," Explain the statement in your own words. 

What is a data profile? 

What is the difference between mapping parameter & mapping variable in data warehousing? 

What is the difference between metadata and data dictionary? 

What is Virtual Data Warehousing? 

Which technology should be used for interactive data querying across multiple dimensions for a decision making for a DW? 

What is the difference between dependent data warehouse and independent data warehouse? 

What is the main difference between star and snowflake star schema? Which one is better and why? 

What is critical column? 

How can you implement many relations in star schema model? 

Where the Data cube technology is used? 

After the complete generation of a report who will test the report and who will analyze it? 
After the generation of a report to whom we have to deploy or what we do after the completion of a report? 

data mining? Where it will be used? 

What is data analysis? Where it will be used? 

What is data warehouse architecture? 

What is type 2 version dimension? 

For faster process, what we will do with the Universe? 

I have two Universes created by two difference database can we join them in Designer & Report level? How 

What is difference between drill & scope of analysis? 

What is a real-time data warehouse? How is it different from near to real-time data warehouse? 

How can we run the graph? What is the procedure for that? How can we schedule the graph in UNIX? 

Explain Why fact table is in normal form? 

Explain ER Diagram? 

What is incremintal loading? 

What is batch processing? 

What is crass reference table? 

What is aggregate fact table? 

Explain the definition of normalized and denormalized view and what are the differences between them? 

Explain What is data validation strategies for data mart validation after loading process? 

What is data validation strategies for data mart v? 

What is the difference between a data warehouse and a data mart? 

What is ETL process in data warehousing? 

What is analysis service? 

Explain sequence clustering algorithm. 

.Explain discrete and continuous data in data mining. 

Explain time series algorithm in data mining. 

What is XMLA? 

Explain the difference between Data warehousing and Business Intelligence.
 
What is the purpose of Factless Fact Table? 

What is a level of Granularity of a fact table? 

What are fundamental stages of Data Warehousing?
 
What is Virtual Data Warehousing? 

What is active data warehousing? 

List down differences between dependent data warehouse and independent data warehouse. 

Difference between ER Modeling and Dimensional Modeling. 

What is snapshot with reference to data warehouse? 

Describe the various methods of loading Dimension tables. 

What is the difference between OLAP and data warehouse? 

Describe the foreign key columns in fact table and dimension table. 

What is cube grouping? 

What is real time data-warehousing? 

What is conformed fact? What is conformed dimensions use for? 

Define non-additive facts. 

Explain in brief about critical column. 

What is data cube technology used for? 

What is the function of ETL when used in data warehousing?
 
What are the different types of schemas used in Data warehousing? 

What is the difference between data warehouse and operational systems? 

What are the stages that are required in Data warehousing? 

What are the different ways to represent the loading of Dimension tables? 

What are the steps involved in designing a fact table? 

Why is Business Intelligence (BI) important in data warehousing? 

What are the steps involved in creating dimensional modeling process? 

Why is dimensional normalization not required? 

Why facts table is useful in representing the data? 

What is the purpose of cluster analysis in Data Warehousing? 

What are the different models used in cluster analysis? 

What is the difference between agglomeration and divisive Hierarchical Clustering? 

Why is chameleon method used in data warehouse? 

What are the key features of chameleon that separates it from other algorithms? 

What is a Cube and Linked Cube with reference to data warehouse? 

What is junk dimension? 

What is Virtual Data Warehousing? 

Difference between dependent and independent data warehouse 

Why is SAS so popular? 

What is Bit Mapped Index? 

What is Data Cardinality?
 
What is Chained Data Replication? 

What are Critical Success Factors? 

What is the use of dimensional modeling in data warehousing? 

What is conformed dimensions 

What is multi dimensionals

Comments

  1. Thanks for sharing..very useful. Appreciate your effort.

    ReplyDelete
  2. Good job Kashif, Keep it up!
    Aamir

    http://sqlage.blogspot.com/

    ReplyDelete
  3. A/s Kashif Bhai,

    I need your help or Guidence.

    I am an OBIEE/ETL/Dataware house tester. And i am very much interested in doing a certification. But first of all i am not aware of all the certifications available for OBIEE 11g and what is the procedure from step 1 till i get certified. I mean where to register and how?. Secondly as being a tester i am not able to decide that which role would suit me, means an OBIEE functional consultant or OBIEE Administrator? Certification Fee etc?

    Any information that you have regarding my queries or any link. Or any help based on your own experience will be much appreciated.

    ReplyDelete
    Replies
    1. W/S Amir,

      First of all I appreciate you interest on doing OBIEE 11G certification.

      1. You need to find out nearest prometric center in your location, refer this site https://www.prometric.com ,once you find out the nearest test center go there directly and schedule your exam time with them.

      2. OBIEE 11G exam code - 1z0-591 (Oracle Business Intelligence Foundation Suite 11g Essentials)

      Refer this link - http://education.oracle.com/pls/web_prod-plq-dad/db_pages.getpage?page_id=5001&get_params=p_exam_id:1Z0-591&p_org_id=&lang=

      3. You might be suited to OBIEE administrator role

      4. Fees will be around 8,000 INR, sometimes they give discount on prometric center.


      Contact with my email coogle7222@gmail.com, to know how to clear OBIEE certification exam easily

      Delete
  4. Thanks alot Kashif Bhai. Will get back to you soon on your email id.

    ReplyDelete
  5. Kashif Bhai,

    Before finding the test center in Prometric its asking for test Sponsor. I Searched for Oracle. Since it is mentioned there that the whose test we are taking that will be the test sponsor. But Oracle is not present there. Could you please tell me that what will be the test sponsor for this test.

    ReplyDelete
    Replies
    1. Amir,

      Sorry for late reply.

      Find this link it will be useful for you

      https://wsr.pearsonvue.com/testtaker/registration/SelectTestCenterProximity/ORACLE/58124

      http://education.oracle.com/pls/web_prod-plq-dad/db_pages.getpage?page_id=458&get_params=p_track_id:OBIFS11gOPN

      Regards
      Kashif M

      Delete
  6. Thanks a lot for writing this blog and very useful questions given by you siri

    ReplyDelete
  7. HI KASILF BHAI,

    I WANT TO LEARN INFORMATICA, PLZ GIVE ME UR VALUABLE SUGGESTION

    ReplyDelete
  8. I want to learn ETL tool Abinitio , could you please tell me how this course would be ? how much demand it has and also is there any certification for this course abinitio ? I will be happy if you can reply to my mail id ( raghava.cse25@gmail.com) . Thank you !!

    ReplyDelete

Post a Comment

Popular posts from this blog

Contact Me

Do You have any queries ?                   If you are having any query or wishing to get any type of help related Datawarehouse, OBIEE, OBIA, OAC then please e-email on below. I will reply to your email within 24 hrs. If I didn’t reply to you within 24 Hrs., Please be patience, I must be busy in some work. kashif7222@gmail.com

Top 130 SQL Interview Questions And Answers

1. Display the dept information from department table.   Select   *   from   dept; 2. Display the details of all employees   Select * from emp; 3. Display the name and job for all employees    Select ename ,job from emp; 4. Display name and salary for all employees.   Select ename   , sal   from emp;   5. Display employee number and total salary   for each employee. Select empno, sal+comm from emp; 6. Display employee name and annual salary for all employees.   Select empno,empname,12*sal+nvl(comm,0) annualsal from emp; 7. Display the names of all employees who are working in department number 10   Select ename from emp where deptno=10; 8. Display the names of all employees working as   clerks and drawing a salary more than 3000   Select ename from emp where job=’clerk’and sal>3000; 9. Display employee number and names for employees who earn commission   Select empno,ename from emp where comm is not null and comm>0. 10

Informatica sample project

Informatica sample project - 1 CareFirst – Blue Cross Blue Shield, Maryland (April 2009 – Current) Senior ETL Developer/Lead Model Office DWH Implementation (April 2009 – Current) CareFirst Blue Cross Blue Shield is one of the leading health care insurance provided in Atlantic region of United States covering Maryland, Delaware and Washington DC. Model Office project was built to create data warehouse for multiple subject areas including Members, Claims, and Revenue etc. The project was to provide data into EDM and to third party vendor (Verisk) to develop cubes based on data provided into EDM. I was responsible for analyzing source systems data, designing and developing ETL mappings. I was also responsible for coordinating testing with analysts and users. Responsibilities: ·          Interacted with Data Modelers and Business Analysts to understand the requirements and the impact of the ETL on the business. ·          Understood the requirement and develope