What goes on in a warehouse

1. 1 What goes on in a warehouse

2. 2 Data Within the Warehouse There are different types of data typically stored in the warehouse: Current time value detail data/old detail data Lightly summarized data Highly summarized data Metadata

3. 3 Detail Reflects latest �happenings� within the organization, so is of interest Example: order transactions High volumes, complex and expensive to manage. Typically, value degrades quickly for analysis purposes Typically, current detail is retained in the �core� warehouse for a relatively short period of time (months rather than years) Detail data is regularly archived to less expensive storage, where it may be accessed when required

4. 4 Lightly Summarized Data Derived from current detail Typically, aggregates data over a period of time (day or week) Example: daily product sales by store location Lightly summarized data typically remains in the warehouse for much longer than detail data (years)

5. 5 Highly Summarized Data Aggregates data over a relatively long period of time (month, year) Example: Product sales by province by month Highly summarized data typically has the longest life within the warehouse. The higher the level of summarization, the greater (wider) the usage

6. 6 Metadata Data about data Provides a guide for warehouse users to understand: The meaning of the data in the warehouse How the data in the warehouse was �mapped� from operational systems, and the �transformations� that took place The algorithms that were used to summarize/derive data in the warehouse Good Metadata is a Critical Success Factor for a Warehouse � users don�t trust warehouse data unless they understand it

7. 7 Data Flow