Логическая модель

1. groups
• group_id (INT, Primary Key)
• group_name (VARCHAR(50))
2. students
• student_id (INT, Primary Key)
• first_name (VARCHAR(100))
• last_name (VARCHAR(100))
• email (VARCHAR(255))
• group_id (INT, Foreign Key to groups.group_id)
3. teachers
• teacher_id (INT, Primary Key)
• first_name (VARCHAR(100))
• last_name (VARCHAR(100))
• email (VARCHAR(255))
4. courses
• course_id (INT, Primary Key)
• course_name (VARCHAR(255))
• description (TEXT)
• teacher_id (INT, Foreign Key to teachers.teacher_id)
5. classes
• class_id (INT, Primary Key)
• course_id (INT, Foreign Key to courses.course_id)
• teacher_id (INT, Foreign Key to teachers.teacher_id)
• group_id (INT, Foreign Key to groups.group_id)
• class_date (DATE)
• class_time (TIME)
• topic (VARCHAR(255))
6. attendance
• attendance_id (INT, Primary Key)
• student_id (INT, Foreign Key to students.student_id)
• class_id (INT, Foreign Key to classes.class_id)
• is_present (BOOLEAN)
7. grades
• grade_id (INT, Primary Key)
• student_id (INT, Foreign Key to students.student_id)
• course_id (INT, Foreign Key to courses.course_id)
• grade (DECIMAL(3,1))
• date_received (DATE)
• class_id (INT, NULLable, Foreign Key to classes.class_id)
8. academic_periods
• period_id (INT, Primary Key)
• period_name (VARCHAR(100))
• start_date (DATE)
• end_date (DATE)