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Exercise No. 57: E-Commerce (dfm)

In this simplified E/R schema a customer pays for a product by credit card via a webbrowser. The customer belongs to a certain customer group and the product is of a certain type. The transaction is encrypted which is done by a certain encryption standard. The time dimension consists of day, week and month.

Figure D.E.48.1 - e-commerce

Please identify the fact of interest and build the attribute tree. Some attributes are not of interest for this data warehouse: We are not interested in the date of birth of a customer and the version of a webbrowser. Other attributes cannot be used for aggregation in a meaningful way. Those should be tagged as non-dimension attributes in the fact schema.

Then derive the fact schema from the tree by defining dimensions, fact attributes and hierarchies and build a glossary for the fact attributes if there are any.

Please include an additional fact attribute counting the number of products.

Solution

This exercise is part of a case study: dfm - apa - log

Exercises List