Problem $3$:

Suppose that a data warehouse consists of the three dimensions: time, doctor, and patient, and

the two measures: count and charge, where charge is the fee that a doctor charges a patient for

a visit.

a$)$ Enumerate three classes of schemas that are popularly used for modeling data warehouses.

b$)$ Draw a schema diagram for the above data warehouse using one of the schema classes

listed in $($a$).$

Problem $4$:

A data warehouse can be modeled by either a star schema or a snowflake schema. Briefly

describe the similarities and the differences of the two models, and then analyze their

advantages and disadvantages with regard to one another. Give your opinion of which might be

more empirically useful and state the reasons behind your answer.