A database, in the traditional sense, could be compared to a Rolodex.  It's filled with many records (i.e. business cards) with many fields (e.g. name, address, phone), and most people probably index (i.e. sort) it alphabetically.  But, there are times when it might be good to have a quick way to look up cards in the Rolodex by company, or by title.  Instead of a single dimension (sorted alphabetically), a multi-dimensional Rolodex would be faster and more valuable.

A data warehouse is a multi-dimensional database. With a multi-dimensional Rolodex, you flip the lid up facing forward, and the cards are alphabetical.  But, if you spin it around, and open the lid from the back, the cards would be grouped and sorted by company.  Turn it over, and open the bottom and the cards are sorted by title.  Similarly, a data warehouse stores your organization's data in such a way that you can query for information in multiple dimensions, and the results are fast and accurate. Therefore, the key to a good data warehouse is good data management.

Extract Transform Load (ETL)
When you build a data warehouse, you most likely are drawing data from traditional databases.  Data experts develop ways to "Extract" data from different sources, "Transform" it so that the data fits well with other data and isn't duplicative or full of holes (think of this as ensuring that all the cards have all the necessary fields filled in for name, company and title, but none are duplicated.) Lastly, the data is "Load"-ed into the warehouse, and then processes are run to prepare the data to be queried in multiple dimensions.  Since you know what KPIs you want to create, and you've identified where the data comes from, the data warehouse is built with those outcomes in mind.  Retrieving data is fast, and the results are clean and accurate.

Scorecards, Dashboards, KPIs and Data Warehouses provide an organization a well-structured set of tools for monitoring performance.  And if all lights are green, that might be enough.  But, what happens when a red light shows up on the dashboard?  It becomes an essential component of Business Intelligence to drill down into the data and learn where the problem is. 

Follow the next step in the thread to learn more about dynamic reporting.