-- 2026_02_enrollments.sql
-- Matrículas por materia (para restringir EE e IA a cursos del estudiante)

CREATE TABLE IF NOT EXISTS enrollments (
  id INT AUTO_INCREMENT PRIMARY KEY,
  academic_year_id INT NOT NULL,
  student_user_id INT NOT NULL,
  subject_id INT NOT NULL,
  created_at TIMESTAMP DEFAULT CURRENT_TIMESTAMP,
  UNIQUE KEY uniq_enroll (academic_year_id, student_user_id, subject_id),
  INDEX idx_student_year (student_user_id, academic_year_id),
  FOREIGN KEY (academic_year_id) REFERENCES academic_years(id),
  FOREIGN KEY (student_user_id) REFERENCES users(id),
  FOREIGN KEY (subject_id) REFERENCES subjects(id)
) ENGINE=InnoDB DEFAULT CHARSET=utf8mb4;