Suppose that a data warehouse consists of the three dimensions time, customer, and cell phone plan, and the two measures number of calls and cell phone bill
a) Draw a schema diagram for the above data warehouse using the star schema.
b) Starting with the base cuboid [month, customer, plan], what specific OLAP operations should be performed in order to
i. Find the total no of calls made by each customer in 2009.
ii. Find the total no of calls made by all the customers in each plan every year.
iii. Find the monthly bill for each customer.