CREATE TABLE IF NOT EXISTS exam_results (
    id INT AUTO_INCREMENT PRIMARY KEY,
    exam_id INT NOT NULL,
    user_id INT NOT NULL,
    score DECIMAL(5, 2) NOT NULL,
    submitted_at TIMESTAMP DEFAULT CURRENT_TIMESTAMP,
    FOREIGN KEY (exam_id) REFERENCES exams(id) ON DELETE CASCADE,
    FOREIGN KEY (user_id) REFERENCES users(id) ON DELETE CASCADE
);