Question: Conceptual Design
Perform conceptual design for the TCI. You are required to generate an ER diagram. And you also need to write the specification that includes additional constraints not shown on the diagram. The specification should be written in English. If you believe that you need to make additional assumptions, clearly state them.
TCI assembles computers and sells them to clients.
Each computer has a unique serial number, its CPU speed, memory size, price, and DVD speed. There are three different types of computers: laptops, desktops, all-in-ones. For laptops, we need to record their size; for desktops, we need to record their monitor size; for all-in-ones, we need to record their size and weights.
Each computer belongs to at most one warrantee policy type, while each warrantee policy type covers many computers. Every computer doesn't have to have a warrantee, and we may have some warrantee policy that does not cover any computer at all. For each policy type, we want to record its policy ID, name, and length. The length of a policy can only be one year, two years, or six years.
We want to keep the following information about our employees: their name (including first and last name), a unique EID, their address, phone number (we only store one number), and their age.
One employee can assemble many computers, and one computer can be assembled by many employees together. A computer has to be assembled by at least an employee, and an employee has to assemble at least one computer. For the assembling activity, we need to record how many hours each employee spent on each computer.