The word of Enterprise Data Warehouse is very nice at the first glance, yet when businesses want to estimate its cost, they usually prefer to have some important data marts that drive their most important business goals; in order to break its enormous cost. Beside, having these kinds of data marts could be a huge problem especially when those could not integrated with each other during the time that those are created.
Having bus architecture is undoubtedly one of the vital parts of building an enterprise data warehouse during the time, for it will provide the join possibility between the data marts by specifying the conformed dimensions.
Conformed dimensions are what which are common between data marts and make the drill across possible. Off course, it could not be eliminated from enterprise main features.
Finally, the most common problem that you may encounter during building the conformed dimensions is different level of grains that different data marts are needed, so it is recommended that you design dimension’s levels correctly which will even be helpful for drilling through actions.