An automobile manufacturer needs to build a data warehouse to store and analyze data about repairs of vehicles. Among other information, the date of repair, properties of the vehicle (e.g. model), information about the specific repair case (e.g. costs, number of garage employees involved, duration of the repair), data about the garage doing the repair, and data about the customer who owns the vehicle are stored.
Typical examples of business intelligence questions are:
- What are the average total repair costs per month for garages in Boston by type of garage during the year 2011?
- Identify five vehicle types that had the lowest average part costs.
- Which factors (e.g., vehicle's age, mileage, model; customer's gender, age) contribute most to the repair costs?
The operational database keeps track of the repair costs (broken down by part costs, wages and total)for a specific vehicle (owned by a customer) for a specific garage on a dailybasis.
1. Draw a star schema for this data warehouse and specify all relevant attributes.
2. Identify any candidates for conformed dimensions that may be shared with other schemas (e.g., sales).
3. Identify any slowly changing dimensions and the attributes whose values may change from time to time.
4. Draw a lattice hierarchy for each dimension that has more than one level.