Draw an E-R diagram for each of the following situations (if you believe that youneed to make additional assumptions, clearly state them for each situation):
a. A company has a number of employees. The attributes of EMPLOYEE includeEmployee-ID (identifier), Name, Address, and Birth date. The company alsohas several projects. Attributes of PROJECT include Project-ID (identifier),roject-Name, and Start - Date. Each employee may be assigned to one or moreprojects, or may not be assigned to a project. A project must have at least oneemployee assigned, and may have any number of employees assigned. Anemployee's billing rate may vary by project, and the company wishes to record
the applicable billing rate (Billing-Rate) for each employee when assigned to aparticular project.
b. A university has a large number of courses in its catalog. Attributes ofCOURSE include Course-Number (identifier), Course Name, and Units. Eachcourse may have one or more different courses as prerequisites, or may have noprerequisites. Similarly, a particular course may be a prerequisite for anynumber of courses, or may not be prerequisite for any other course.
c. A college course may have one or more scheduled sections, or may not have ascheduled section. Attributes of COURSE include Course ID, Course Name,and Units. Attributes of SECTION include Section-Number and Semester-ID.Semester-ID is composed of two parts: Semester, and Year. Section-Number isan integer (such as "1" or "2") that distinguishes one section from another for the
same course but does not uniquely identify a section.
d. The entity type STUDENT has the following attributes: Student-Name, Address,Phone, Age, Activity, and No-of-Years. Activity represents some campus-basedstudent activity, while No-of-Years represents the number of years the student hasengaged in this activity. A given student may engage in more than one activity Drawan F-R diagram for this situation.