Entities:
* Student: StudentID (PK), FirstName, LastName, Email, Password, Address, PhoneNumber, RegistrationDate
* Instructor: InstructorID (PK), FirstName, LastName, Email, Password, Department, Bio, Title
* Course: CourseID (PK), CourseName, CourseDescription, Credits, Level, InstructorID (FK)
* Module: ModuleID (PK), ModuleName, ModuleDescription, CourseID (FK)
* Assignment: AssignmentID (PK), AssignmentName, Description, DueDate, PointsPossible, ModuleID (FK)
* Submission: SubmissionID (PK), StudentID (FK), AssignmentID (FK), SubmissionDate, Grade, Feedback
* Announcement: AnnouncementID (PK), Title, Content, CourseID (FK), PostDate
* Enrollment: EnrollmentID (PK), StudentID (FK), CourseID (FK), EnrollmentDate, Grade
Relationships:
* Teaches: A many-to-many relationship between Instructor and Course. This could be implemented as a junction table (Instructor_Course) with InstructorID and CourseID as foreign keys. This allows an instructor to teach multiple courses, and a course to have multiple instructors.
* Includes: A one-to-many relationship between Course and Module. One course can include many modules.
* Contains: A one-to-many relationship between Module and Assignment. One module can contain many assignments.
* Submits: A one-to-many relationship between Student and Submission. One student can submit many assignments.
* Belongs to: A one-to-many relationship between Assignment and Submission. One assignment can have many submissions.
* Enrolled in: A many-to-many relationship between Student and Course, implemented via the Enrollment entity. This allows a student to enroll in multiple courses and a course to have many students.
* Posts: A one-to-many relationship between Instructor and Announcement. An instructor can post many announcements. This could also be a many-to-many relationship if other users (e.g., admins) can post announcements.
Diagram Representation:
You would represent these entities as rectangles and the relationships as lines connecting them. The cardinality (one-to-one, one-to-many, many-to-many) would be indicated on the lines (e.g., using crows feet notation for many). Primary keys (PK) and foreign keys (FK) are usually indicated within the entity rectangles.
Example using Crow's Foot Notation:
```
Student *----------------1 Enrollment 1--------------* Course
| | |
| | |
1-------------------* Teaches *----------------1 Instructor
| |
| |
| |
*-------------------1 Includes 1--------------* Module
|
|
*-------------------1 Contains 1--------------* Assignment
|
|
*-------------------1 Submits * Submission
|
|
1-------------* Announcement
|
|
1-------------Instructor (Posts)
```
Note: This is a simplified ER diagram. A more complete model might include entities for things like:
* Quizzes: Similar to Assignments, but specifically for quizzes.
* Discussion Forums: For student interaction.
* Learning Resources: Documents, videos, etc., associated with modules.
* Payment Information: For handling course fees.
* User Roles: To manage different types of users (students, instructors, administrators).
Remember to use a diagramming tool (e.g., Lucidchart, draw.io, ERwin) to create a visually clear and professional-looking ER diagram. These tools often help enforce correct notation and relationships.