= Conceptual Design – ER Diagram and Data Requirements =

== ER Diagram ==
 

 


== Data Requirements ==

=== Entities ===

* **Users: Entity representing all users who access the platform (students / learners).**
  * User_ID – PRIMARY KEY
  * First_Name – VARCHAR
  * Last_Name – VARCHAR
  * Email – VARCHAR(unique)
  * Password – VARCHAR

* **Administrators: Entity representing instructors who create and manage educational content.**
  * Admin_ID – PRIMARY KEY
  * Admin_Level – VARCHAR

* **Payment: Entity representing financial transactions.**
  * Payment_ID – PRIMARY KEY
  * Amount – DECIMAL
  
* **Course: Entity representing the courses offered on the platform.**
  * Course_id – PRIMARY KEY
  * Certificate – VARCHAR
  * Name – VARCHAR
  * Price – Decimal
  * status – VARCHAR

* **Enrollment: Entity representing the enrollment of a user in a course.**
  * Enrollment_id – PRIMARY KEY
  * Enroll_date – DATE
  * Completion_Status – VARCHAR
  * Progress_percentage – INT

* **Payment: Entity representing financial transactions.**
  * Payment_ID – PRIMARY KEY
  * Amount – DECIMAL

* **SubscriptionPlan: Entity representing available subscription plans.**
  * Plan_ID – PRIMARY KEY
  * Name – VARCHAR
  * Price – DECIMAL
  * Duration_months – INT
  * Description – VARCHAR
  * Access_type – VARCHAR

* **Certificate: Entity representing certificates issued after course completion.**
  * Certificate_id – PRIMARY KEY
  * Issue_date – DATE
  * Certificate_code – VARCHAR
  * Status – VARCHAR

* **UserSubscription: Entity representing active subscriptions of users.**
  * Subscription_ID – PRIMARY KEY
  * Start_date – DATE
  * End_date – DATE
  * Status – VARCHAR

* **SupportTicket: Entity representing user support requests.**
  * Ticket_ID – PRIMARY KEY
  * Subject – VARCHAR
  * Description – VARCHAR
  * Status – VARCHAR
  * Created_at – DATE

* **Category: Entity representing course classification.**
  * Category_ID – PRIMARY KEY
  * Name – VARCHAR
  * Description – VARCHAR

* **Module: Entity representing logical subdivisions of a course.**
  * Мodule_id – PRIMARY KEY
  * Тitle – VARCHAR
  * Description – VARCHAR
  
* **Lesson: Entity representing individual learning units.**
  * Lesson_ID – PRIMARY KEY
  * Тitle – VARCHAR
  * Material – VARCHAR
 
* **Quiz: Entity representing assessments associated with lessons.**
  *  Quiz_ID – PRIMARY KEY
  * Total_points – INT
  * Passing_score – INT

=== Relationships ===

* A **User** can make multiple **Payments** (1:N)