students
| id | name | date_of_birth |
| 1 | John Doe | 2003-01-01 |
| 2 | Jane Smith | 2002-06-27 |
| 3 | Alice Johnson | 2001-12-18 |
| 4 | Bob Brown | 2000-09-05 |
| 5 | Emma Davis | 1999-03-19 |
subjects
| subject_id | subject_name |
| 1 | Mathematics |
| 2 | English Literature |
| 3 | Physics |
| 4 | Chemistry |
| 5 | Biology |
enrollments
| student_id | subject_id |
| (→ students.id) | (→ subjects.subject_id) |
| 1 | 1 |
| 2 | 2 |
| 3 | 3 |
| 4 | 4 |
| 5 | 5 |
learning_materials
| material_id | subject_id | materials | difficulty_level |
| (→ subjects.subject_id) | | |
| 1 | 1 | Textbook | Intermediate |
| 2 | 2 | Video Lectures | Advanced |
| 3 | 3 | Textbook | Beginner |
| 4 | 4 | Online Course | Intermediate |
| 5 | 5 | Ebooks | Advanced |