Data Marts and Data Warehouses - Physical or logical

[sumeshabraham]

Hi All,

In one of the recent DW interviews I as asked about Data Marts. The qn was whether Data Marts is physical or logical. I couldn't understand it. Can anyone please explain me how the physical and logical aspects apply to Data Marts and Data Warehouses.

Thanks,
Sumesh

 

[Hans63]

In my opinion, Datamarts are a logical concept, but they can be physically implemented.

A datamart is defined around some business area. As such it is logical.
A datamart is implemented using an RDBMS or MDDBS with tables, indexes, cubes, etc. as such it is physical.

Some people say that a DataWarehouse is a collection of Datamarts. For these people, a datamart may be logical only.

 

[johnherman]

I agree with Hans63 that a datamart is defined around some business area. Someone once said that the Enterprise Data Warehouse could be defined as the collection of all datamarts, with conforming dimensions. Whether these datamarts are on different platforms with different update/refresh timetables, etc does not matter. Inmon et al say that you build an Enterprise Data Mart first (Corporate Information Factory method), then build the datamarts off the Enterprise DM

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