RE: what is the difference between E-R modelling and D...
ER modeling: - focused how data will be efficient for processing (insert, update, delete) - Minimalize (limit to zero) data redundancies
Dimensional: - focused how data will be efficient for retrieving (example, by report and analysis tools). - many data redundancies - Consist of Fact and Dimension table
RE: what is the difference between E-R modelling and Dimendional modelling? and what are semi additive facts?
//Semi additive facts//
Whenever possible the facts or measure in the fact table should be chosen as perfectly additive. However some measure of intensity is not perfectly additive across all of the dimensions.
Thus some measures in the fact table is additive across atleast one dimension but not all of the dimensions so called semi additive or partially additive facts.
