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I recently read an article on pathstring attributes in a dimensional table.

http://www.kimballgroup.com/2009/08/five-alternatives-for-better-employee-dimension-modeling/

Hi,
  1.Please explain the difference between ER model and dimensional model in a simple manner
 2.Is it necessary that tables present in both ER model and Dimensional model should be in third normal form
3.Is Enterprise Datawarehouse(EDW) constructed using ER model?
4.Is Datamart constructed using Dimension model?