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

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

Total Answers and Comments: 7

Last Update: December 21, 2006 Asked by: Srinu

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March 11, 2006 18:41:43

Uma

RE: What is Difference between E-R Modeling and Diment...

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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May 13, 2006 04:41:55

venkat

RE: What is Difference between E-R Modeling and Diment...

Adding to the point:

E-R modelling revovles around the Entities and their relationships to capture the overall process of the system.

Dimensional model/Muti-Dimensinal Modelling revolves around Dimensions(point of analysis) for decison making and not to capture the process.

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June 08, 2006 11:39:23

ANIL

RE: What is Difference between E-R Modeling and Diment...

hi everybody,In ER modeling the data is in normalised form. So more number of Joins, which may adversly affect the system performnace.Whereas in Dimensional Modelling the data is denormalised, so less number of joins, by which system performance will improve.bye.

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September 01, 2006 13:55:26

mamatha

RE: What is Difference between E-R Modeling and Diment...

hi srinu

The basic diff is ER model is a normalized model becoz in oltp we don't have the concept of dim model

where as dim model is a denormalized model where we can use multi dim analysis

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October 23, 2006 22:40:01

thumatinagaraju

Member Since: October 2006 Contribution: 26

RE: What is Difference between E-R Modeling and Diment...

In the E-R modeling the data is represented in entities and attributes and it's in the denormalized form.. In the dimensional modeling the data is represented in form of facts and dimension's the fact's contain only neumaricals and foreign key's and the dimension's are used to refer's the data from fact table's using these fact and dimensions we can form OLAP cubes for analysis ..which are useful for decision support for management

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November 06, 2006 15:08:59

tigerpeng2001

RE: What is Difference between E-R Modeling and Diment...

ER modeling: a view of data from data processing.

MD modeling: a view of data from business porcessing.

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December 21, 2006 11:58:32

noverino

Member Since: December 2006 Contribution: 7

RE: What is Difference between E-R Modeling and Diment...

E-R Modeling is a model for OLTP, optimized for Operational database, namely insert, update, delete data and stressing on data relational integrity.Dimensional Modeling is a model for OLAP, optimized for retrieving data because it's uncommon to update or delete the data.

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