What is Difference between E-R Modeling and Dimentional Modeling.?

Data Warehousing Interview Questions and Answers

(Continued from previous question...)

What is Difference between E-R Modeling and Dimentional Modeling.?

Basic diff is E-R modeling will have logical and physical model. Dimensional model will have only physical model.

E-R modeling is used for normalizing the OLTP database design.

Dimensional modeling is used for de-normalizing the ROLAP/MOLAP design.

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Other Interview Questions

• What's A Data warehouse
• What is ODS?
• What is a dimension table?
• What is a lookup table?
• Why should you put your data warehouse on a different system than your OLTP system?
• What are Aggregate tables?
• What is Dimensional Modelling? Why is it important ?
• Why is Data Modeling Important?
• What is data mining?
• What is ETL?
• What does level of Granularity of a fact table signify?
• What is the Difference between OLTP and OLAP?
• What is SCD1 , SCD2 , SCD3?
• Why are OLTP database designs not generally a good idea for a Data Warehouse?
• What is BUS Schema?
• What are the various Reporting tools in the Market?
• What is Normalization, First Normal Form, Second Normal Form , Third Normal Form?
• What is Fact table?
• What are conformed dimensions?
• What are the Different methods of loading Dimension tables?
• What is conformed fact?
• What are Data Marts?
• What is a level of Granularity of a fact table?
• How are the Dimension tables designed?
• What are non-additive facts?
• What type of Indexing mechanism do we need to use for a typical datawarehouse?
• What Snow Flake Schema?
• What is real time data-warehousing?
• What are slowly changing dimensions?
• What are Semi-additive and factless facts and in which scenario will you use such kinds of fact tables?
• Differences between star and snowflake schemas?
• What is a Star Schema?
• What is a general purpose scheduling tool?
• What is ER Diagram?
• Which columns go to the fact table and which columns go the dimension table?
• What are modeling tools available in the Market?
• Name some of modeling tools available in the Market?
• How do you load the time dimension?
• Explain the advanatages of RAID 1, 1/0, and 5. What type of RAID setup would you put your TX logs.
• What are the vaious ETL tools in the Market?
• What is VLDB?
• What are Data Marts ?
• What are the steps to build the datawarehouse ?
• What is Difference between E-R Modeling and Dimentional Modeling.?
• Why fact table is in normal form?
• What are the advantages data mining over traditional approaches?
• What are the vaious ETL tools in the Market?
• What is a CUBE in datawarehousing concept?
• What is data validation strategies for data mart validation after loading process ?
• what is the datatype of the surrgate key ?
• What is degenerate dimension table?
• What is Dimensional Modelling?
• What are the methodologies of Data Warehousing.?
• What is a linked cube?
• What is the main difference between Inmon and Kimball philosophies of data warehousing?
• What is Data warehosuing Hierarchy?
• What is the main differnce between schema in RDBMS and schemas in DataWarehouse....?
• What is hybrid slowly changing dimension?
• What are the different architecture of datawarehouse?
• what is incremintal loading? 2.what is batch processing? 3.what is crass reference table? 4.what is aggregate fact table?
• what is junk dimension? what is the difference between junk dimension and degenerated dimension?
• What are the possible data marts in Retail sales.?
• What is the definition of normalized and denormalized view and what are the differences between them?
• What is meant by metadata in context of a Datawarehouse and how it is important?
• Differences between star and snowflake schemas?
• Difference between Snow flake and Star Schema. What are situations where Snow flake Schema is better than Star Schema to use and when the opposite is true?
• What is VLDB?
• What's the data types present in bo?n what happens if we implement view in the designer n report
• Can a dimension table contains numeric values?
• What is the difference between view and materialized view?
• What is surrogate key ? where we use it expalin with examples
• What is ER Diagram?
• What is aggregate table and aggregate fact table ... any examples of both?
• What is active data warehousing?
• Why do we override the execute method is struts? Plz give me the details?
• What is the difference between Datawarehousing and BusinessIntelligence?
• What is the difference between OLAP and datawarehosue?
• What is fact less fact table? where you have used it in your project?
• Why Denormalization is promoted in Universe Designing?
• What is the difference between ODS and OLTP?
• What is the difference between datawarehouse and BI?
• Is OLAP databases are called decision support system ??? true/false?
• explain in detail about type 1, type 2(SCD), type 3 ?
• What is snapshot?
• What is the difference between datawarehouse and BI?
• What are non-additive facts in detail?