Dimension modeling VS ER modeling

Difference between Dimension modeling and E-R modeling(Relational modeling)

•The E-R diagram is split as per the entities like Customer,Product etc and its attributes would be textual and numeric(fact or calculation) . A dimension model is split as per the dimensions and facts. dimension only contains textual attributes and numeric values will comes under fact table.

. The E-R modeling will be more normalized (used as a OLTP) with optimum index but in Dimension moduling would be less normalized (used as a OLAP) with maximus number of index to boost the search performance.

. Dimension modeling will help you to desing database for desicion support system but E-R modeling is used for Transaction processing database.

.An E-R diagram is a complex maze of hundreds of entities linked with each other (more relationship between entities), whereas the Dimensional model has logical grouped set of star-schemas or snowflacs.

. Performance of Insert,Delete and update operation would be high and search would be comparatively slow in ER modeling but Dimension modeling Search would be faster and lest operation would be slower.