Difference between ER modeling and dimension modeling

  Dimension Modelling ER modelling
Redundancy More Less Redundancy
Optimization Querying, can vary and can have huge volumes Pre-determined set of updates, inserts and select queries
Data Current/recent data Archived and historical data
Size MB to GBs GBs to TBs
Physical Model Denormalized Normalized
Complexity Dimensional model has logical grouped set of star-schemas An E-R diagram is a complex maze of hundreds of entities linked with each other
Split split as per the dimensions and facts split as per the entities

 

 

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