What is Data Mart in Data Warehousing?

qWhat is Data Mart?

vData mart is the Subset of a data warehouse.

vIt’s a smaller form of DWH which contain only one subject area.

vTime taken to create Data Mart in very less compare to DWH

vTypes of Data Mart

         1.Dependant : Dependant on DWH which draw data from DWH(Draw data from Central DWH which is already created) E,g:Retails

          2. Independent: Independent on DWH or stand alone DM which draws data directly from Operational  or external sources. E,g: Banking projects,start ups

          3.Hybrid: Draw data both from  External sources and DWH

q Approaches to create data Mart

vTwo types of approaches.

                 Top Down and bottom up

Top Down:

     1.First Data warehouse will be created then data mart.(dependant DM)

     2.It directly built from OLTB

     3.Advantage is all the information is located in one centrally location.

     4.Disadvantage is it becomes very big projects and should be handled by  experts  .Expensive

Bottom up:

  1. First Data Marts will be created then DWH(Independent DM)

  2.Quick approach

  3.Easier to manage

  4. less expensive