1- Derive an internal data design for the following case. - a professor teaches zero, one or many classes and a class is taught by one professor - a course may generate zero, one or many classes and a class comes from one course - a class is held in one room but a room has many classes 2- Derive an internal data design for the following case. - an invoice is written by one salesrep but a salesrep writes many invoices - a vendor sells many products but a product is bought from one vendor - an invoice has one or many products and a product is found on zero, one or many invoices 3- University of the Pacific has several departments. Each department is managed by a chair, and at least one professor. Professors must be assigned to one, but possibly more departments. At least one professor teaches each course, but a professor may be on sabbatical and not teach any course. Each course may be taught more than once by different professors