Suppose that a data warehouse consists of the four dimensions date, spectator, location, and game, and the two measures count and charge, where charge is the fare that a spectator pays when watching a game on a given date. Spectators may be students, adults, or seniors, with each category having its own charge rate.

(a) Draw a star schema diagram for the data warehouse.

(b) Starting with the base cuboid [date, spectator, location, game], what specific OLAP operations should you perform in order to list the total charge paid by student spectators at GM_Place in 2010?

(c) Bitmap indexing is useful in data warehousing. Taking this cube as an example, briefly discuss advantages and problems of using a bitmap index structure.