Q. An industry has a number of employees. The attributes of EMPLOYEE comprise Employee ID (identifier), Name, Address and Birth-date. The industry also has several projects. Attributes of PROJECT comprise Project ID (identifier), Project Name and Start Date. Each employee may be assigned to one or more projects or may not be assigned to a project. A project must have at least one employee assigned and may have any number of employees assigned. An employee's billing rate may vary by project and the industry wishes to record the applicable billing rate (Billin Rate) for each employee when assigned to a particular project.