Entities:
* Student: StudentID (PK), FirstName, LastName, DateOfBirth, Address, PhoneNumber, Email, MajorID (FK), AdmissionDate, GPA
* Professor: ProfessorID (PK), FirstName, LastName, DepartmentID (FK), Office, PhoneNumber, Email
* Course: CourseID (PK), CourseName, CourseDescription, Credits, DepartmentID (FK)
* Department: DepartmentID (PK), DepartmentName, HeadProfessorID (FK)
* Enrollment: EnrollmentID (PK), StudentID (FK), CourseID (FK), Grade, Semester
* Textbook: TextbookID (PK), ISBN, Title, Author, Publisher
* CourseTextbook: CourseTextbookID (PK), CourseID (FK), TextbookID (FK)
Relationships:
* Student - Major: One-to-many. A student belongs to one major, a major can have many students. (Implemented through MajorID FK in Student)
* Professor - Department: One-to-many. A professor belongs to one department, a department can have many professors. (Implemented through DepartmentID FK in Professor)
* Department - HeadProfessor: One-to-one. A department has one head professor, a professor can be head of at most one department. (Implemented through HeadProfessorID FK in Department)
* Student - Enrollment: One-to-many. A student can enroll in many courses, a course can have many students enrolled. (Implemented through StudentID FK in Enrollment)
* Course - Enrollment: One-to-many. A course can have many enrollments, an enrollment belongs to one course. (Implemented through CourseID FK in Enrollment)
* Course - CourseTextbook: One-to-many. A course can have many textbooks, a textbook can be used in many courses. (Implemented through CourseID FK in CourseTextbook)
* Textbook - CourseTextbook: One-to-many. A textbook can be used in many courses, a course can have many textbooks. (Implemented through TextbookID FK in CourseTextbook)
* Professor - Course: Many-to-many (requires a junction table). A professor can teach many courses, a course can be taught by many professors. (This would require a separate entity like "ProfessorCourse" with ProfessorID and CourseID as FKs.)
Primary Keys (PK) and Foreign Keys (FK) are indicated.
Diagrammatic Representation (Textual):
You would typically represent this in a diagram using standard ERD notation (rectangles for entities, diamonds for relationships, lines connecting them, etc.). The above is a textual representation to give you the structure. You can use a diagramming tool like Lucidchart, draw.io, or ERwin to create a visual representation based on this information. Remember to add attributes (like those listed above) to your entities within the rectangles in a proper ER diagram.
This is a simplified model. You could extend it to include entities for things like:
* Payments: To track student fees.
* Assignments: To manage assignments given in courses.
* Grades: More detailed grade information beyond what's in Enrollment.
* Library: To manage library resources.
* Administrative Staff: To represent administrative personnel.
Remember to tailor the ER diagram to your specific project requirements. This example provides a solid foundation for building a more detailed and comprehensive model.