A. For the given database users requirements in the following statements or paragraphs, please construct the corresponding E-R diagram (entities and relationships), defined the

key for each entity, indicated the participant constraints (total vs. partial, mandatory vs. optional), and indicate the cardinality of each entity involved in a relationship.

a.) A company has several departments. Each department has a department name, a department number, and a department location. There is only one manager for each department, a manager is also an employee. Not every employee is a manager. Each employee has a name, social security number, gender, age, and salary. Each employee works for only one department, and there are more than one employee working in a department. There are some employees who have dependents. Each dependent has a name, gender, age, and relationship to the employee whom the dependent belongs to. There are some departments that may control some projects. Each project is controlled by only one department. Each project has project number, project name, and project location. Each employee works on several projects, and each project has several employees involved. For each employee, he/she will spend a certain number of hours on each project he/she works

on. A supplier supplies certain number of parts for a project, a project uses some parts from different suppliers, and the same kind parts from different suppliers are used by different projects. A supplier has a supplier number, supplier name, and the city the supplier locates. Each part has a part number, part name, part color, part weight, and city where the part is

manufactured. Some employees may be a supervisor of some other employees. But not every employee has a supervisor, nor have supervisees.