ZeroFill | Android Application will fill your empty disk space

CREATE TABLE IF NOT EXISTS `inventory` (
  `id_product` INT(4) ZEROFILL NOT NULL AUTO_INCREMENT,
  `model` varchar(45) NOT NULL,
  `price_new` FLOAT DEFAULT '0',
  sell_price float,
  `condition1` varchar(45) NOT NULL,
  `launch_date` DATE NOT NULL,
  `stock` INT DEFAULT '0',
  PRIMARY KEY (`id_product`));  
  
CREATE TABLE IF NOT EXISTS `order` (
  `id_order` INT(4) ZEROFILL NOT NULL AUTO_INCREMENT,
  `id_customer` INT(6) ZEROFILL NOT NULL,
  `subtotal` FLOAT DEFAULT '0',
  `discount` float DEFAULT '0',
  `tax_rate` float DEFAULT '0.23',
  `total` float DEFAULT '0',
  `date` DATETIME DEFAULT NOW(),
  PRIMARY KEY (`id_order`),
  CONSTRAINT `fk_order_1`
    FOREIGN KEY (`id_customer`)
    REFERENCES `iSAVE`.`customer` (`id_customer`)
    ON DELETE RESTRICT
    ON UPDATE CASCADE);

  CREATE TABLE IF NOT EXISTS `transaction` (
  `id_transaction` INT(4) ZEROFILL NOT NULL AUTO_INCREMENT PRIMARY KEY,
  `id_order`INT(4) ZEROFILL NOT NULL,
  `status` char(20) default 'Not completed',
  FOREIGN KEY (`id_order`) REFERENCES `iSAVE`.`order` (`id_order`)
);

  CREATE TABLE IF NOT EXISTS `order_item` (
  `id_order_item` INT(4) ZEROFILL NOT NULL AUTO_INCREMENT PRIMARY KEY,
  `id_product` INT(4) ZEROFILL NOT NULL,
  `id_order` INT(4) ZEROFILL NOT NULL,
  `quantity` INT DEFAULT NULL,
  FOREIGN KEY (`id_product`) REFERENCES `iSAVE`.`inventory` (`id_product`),
  FOREIGN KEY (`id_order`) REFERENCES `iSAVE`.`order` (`id_order`)
);

CREATE TABLE IF NOT EXISTS `customer` (
  `id_customer` INT ZEROFILL NOT NULL auto_increment PRIMARY KEY ,
  `fname` varchar(45) not NULL,
  `lname` varchar(45) not NULL,
  `bday` date not NULL,
  `country` char(15) not NULL,  
  `address` varchar(50) not NULL,
  `zip_code` varchar(10) not null
 );

CREATE TABLE IF NOT EXISTS `inventory` (
  `id_product` INT zerofill NOT NULL auto_increment   PRIMARY KEY,
  `model` varchar(45) not null,
  `price_new` FLOAT not null,
  `grade` char(10) not null,
  `launch_year` year not null,
  `final_price` FLOAT(8),
  `stock` INT(5) not null
 );

delimiter //
CREATE TRIGGER upd_check after insert ON inventory
       FOR EACH ROW
       BEGIN
           IF inventory.grade = 'bad' THEN
               update NEW.final_price = 2;
           elseif inventory.grade = 'good' then
                update new.final_price = 0;
           END IF;
       END;//
delimiter ;