CREATE TABLE IF NOT EXISTS `grading_scales` (
    `id` INT AUTO_INCREMENT PRIMARY KEY,
    `section` VARCHAR(50) NOT NULL,
    `grade_name` VARCHAR(10) NOT NULL,
    `min_score` INT NOT NULL,
    `max_score` INT NOT NULL,
    `created_at` TIMESTAMP DEFAULT CURRENT_TIMESTAMP,
    `updated_at` TIMESTAMP DEFAULT CURRENT_TIMESTAMP ON UPDATE CURRENT_TIMESTAMP,
    UNIQUE KEY `section_grade` (`section`, `grade_name`)
) ENGINE=INNODB;