Studierende stehen vor dem LC und blicken lächelnd einer Kollegin mit einer Mappe in der Hand nach.

Exercise No. 19: Service Management (dfm)

This E/R-schema shows problem reports by customers.

Problems are classified by their type, the customers by the district they live in. The problems are not considered unique and may be reported multiple times by the same or a different customer. The report of a problem may or may not cause the allocation of a technician working for a subcontractor, not all reported problems can be solved. The time dimension consists of month, quarter and year.

Figure D.E.14.1 - Service Management

Attribute solved is (at the fact instance level) a binary variable (parameter value 0 or 1, depending on whether the problem could be solved or not) that may be aggregated using the "average" operator along all dimensions. This allows us to analyze the ratio of reported problems that could be solved.

Please identify the fact of interest and build the attribute tree. No attributes have to be pruned or grafted. Some 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.

Please include an additional fact attribute counting the number of reports

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