Much like any database system, data warehouse requires considerable maintenance that shouldn’t be overlooked. As the warehouse grows, the database administrator must determine the optimal physical layout for data files, file groups, tables, and indexes. This is an example of operational maintenance.
Data sources populating the warehouse tend to change; therefore, you will likely have to change the DTS packages as well. For example, if Northwind acquires another company (perhaps Southwind), your users will probably want to examine Southwind’s orders using the existing tools. Similarly, if your boss decides that he would like a report showing Northwind orders by shippers to see which shipments get to their destination on time, you’ll have to add new dimensions and measures to your warehouse.