Data Warehousing

Data Warehousing is the process of taking data from legacy and transaction database systems and transforming it into organized information in a user-friendly format to encourage data analysis and support fact-based business decision making.

Click here to access a Power Point presentation on Data Warehouses.

A data warehouse is a system that extracts, cleans, conforms, and delivers source data into a dimensional data store and then supports and implements querying and analysis for the purpose of decision making.

From your data warehouse, data cubes are tables/files which index and precompute desired data results. In your cube you could have all those precomputed values: sales by months, by week, by salesman, by client, by geographical region, by product color, etc. Then you can run OLAP queries on your cube to have the total, average and maximum sales by (month, salesman, region), or by (color, region), or by (salesman, month). Since all the data is precomputed and indexed, the queries are really fast.

The data warehouses are only for extracting data, and are kept up with triggers and programs within the enterprise application. They were not designed to allow any updates to the information.