Inmon’s Top – down approach of data ware house design

In this approach first we are creating data ware house and after that we are creating various data marts. These data marts are dependent on the data ware house and extract the essential data from it. 

In this approach, we are extracting the data from difference data source and loading the data into the staging table using ETL and after that we are loading these data to the Data ware house. Once Data ware load is completed we are loading (refreshing) the Data marts using ETL tool.