== '''Entity-Relationship Model v01'''


== Diagram

[[Image(ERModel_v01.png)]]



== Data Requirements
• University: This entity stores information about universities. We need it to know which faculties, professors, and students belong to which university.

  º Candidate keys: Id (primary key).

  º Attributes:

   Id – number, required, unique

   Name – text, required, max 255 characters

   Location – text, optional, max 255 characters

   IsPrivate – boolean, required

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• Faculty: Represents a faculty inside a university. It helps organize students, professors, and subjects within that faculty. Each faculty belongs to one university.

  º Candidate keys: Id (primary key).

  º Attributes:

   Id – number, required, unique

   Name – text, required, max 255 characters

   Location – text, optional, max 255 characters

   Study_field – text, optional, max 255 characters

   University_Id – number, required, foreign key to University

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• Professor: This entity stores professors. Each professor works in a faculty and can teach subjects or advise students.

   º Candidate keys: Id (primary key)

   º Attributes:

    Id – number, required, unique

    Name – text, required, max 255 characters

    Surname – text, optional, max 255 characters

    Age – number, optional, 25–100

    Address – text, optional, max 255 characters

    Faculty_Id – number, required, foreign key to Faculty

----

• Student: This entity stores students. Each student belongs to a faculty and can enroll in many subjects. They can also have a professor as their adviser.

   º Candidate keys: Id (primary key).

   º Attributes:

    Id – number, required, unique

    Name – text, required, max 255 characters

    Surname – text, optional, max 255 characters

    Location – text, optional, max 255 characters

    Index – number, required, unique

    Faculty_Id – number, required, foreign key to Faculty

    Professor_Id – number, optional, foreign key to Professor

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• Subject: This entity stores courses or subjects. Each subject belongs to a faculty and is taught by a professor. Students can enroll in subjects.

  º Candidate keys: Id (primary key)

  º Attributes:

   Id – number, required, unique

   Name – text, required, max 255 characters

   Semester – text, optional, e.g., "Fall", "Spring"

   Credits – number, required, 1–15

   Faculty_Id – number, required, foreign key to Faculty

   Professor_Id – number, required, foreign key to Professor

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• Student_Subject: This relationship shows which students are enrolled in which subjects. It also stores their grades, attendance, and enrollment status.

   º Candidate keys: (Student_Id, Subject_Id) (composite primary key)

   º Attributes:

    Final_Grade – number, optional, 5–10 or pass/fail

    Status – text, optional, e.g., "Enrolled", "Completed", "Dropped"

    Enrollment_Date – date, optional

    Absence_Count – number, optional, 0–100

    Student_Id – number, required, foreign key to Student

    Subject_Id – number, required, foreign key to Subject


== Entity-Relationship Model History

v01: First version of the conceptual ER model including University, Faculty, Professor, Student, Subject, and Student_Subject relationship. Attributes, primary keys, and relationships defined.