As per the definition, Both the Datamart & Data warehouse are one and the same.

But there are so many confusing and conflicting definitions of Data Mart and Data Warehouse around us. This was due to the famous mammoths of Data warehousing, i.e., Bill Inmon and Ralph Kimball.

But In genearl to say, there is no difference coming to design part of these two, where as a Data warehouse is used on Enterprise level, where as Datamart is used on a Business Division/Departmental level.

A Datamart only contains data specific to a particular Subject area, where as Data Warehouse is an integration of all different subject-areas.

               

By the above figure we can easily differentiate these two.