Правильная структура БД

CREATE TABLE IF NOT EXISTS `categories` (
  `category_id` INT(10) NOT NULL AUTO_INCREMENT,
  `name_category` VARCHAR(100) DEFAULT NULL,
  PRIMARY KEY (`category_id`)
) ENGINE=InnoDB DEFAULT CHARSET=utf8;
 
CREATE TABLE IF NOT EXISTS `lines` (
  `line_id` INT(11) NOT NULL AUTO_INCREMENT,
  `name` VARCHAR(100) DEFAULT NULL,
  PRIMARY KEY (`line_id`)
) ENGINE=InnoDB DEFAULT CHARSET=utf8;
 
CREATE TABLE IF NOT EXISTS `districts` (
  `district_id` INT(10) NOT NULL AUTO_INCREMENT,
  `name` VARCHAR(100) NOT NULL DEFAULT '0',
  `line_id` INT(11) NOT NULL,
  PRIMARY KEY (`district_id`),
  KEY `line_id` (`line_id`),
  CONSTRAINT `districts_ibfk_1` FOREIGN KEY (`line_id`) REFERENCES `lines` (`line_id`)
) ENGINE=InnoDB DEFAULT CHARSET=utf8;
 
CREATE TABLE IF NOT EXISTS `equipments` (
  `equipment_id` INT(11) NOT NULL AUTO_INCREMENT,
  `name` VARCHAR(100) NOT NULL DEFAULT '0',
  `district_id` INT(10) NOT NULL,
  PRIMARY KEY (`equipment_id`),
  KEY `district_id` (`district_id`),
  CONSTRAINT `equipments_ibfk_1` FOREIGN KEY (`district_id`) REFERENCES `districts` (`district_id`)
) ENGINE=InnoDB DEFAULT CHARSET=utf8;
 
 
 
 
CREATE TABLE IF NOT EXISTS `property` (
  `property_id` INT(11) NOT NULL AUTO_INCREMENT,
  `property_name` VARCHAR(50) NOT NULL DEFAULT '0',
  PRIMARY KEY (`property_id`)
) ENGINE=InnoDB DEFAULT CHARSET=utf8;
 
 
CREATE TABLE IF NOT EXISTS `spares` (
  `spares_id` INT(11) NOT NULL AUTO_INCREMENT,
  `material` VARCHAR(15) NOT NULL,
  `description` VARCHAR(100) NOT NULL DEFAULT '0',
  `price` DOUBLE DEFAULT '0',
  `quantity` DOUBLE NOT NULL,
  `category_id` INT(10) NOT NULL,
  PRIMARY KEY (`spares_id`),
  KEY `category_id` (`category_id`),
  CONSTRAINT `spares_ibfk_1` FOREIGN KEY (`category_id`) REFERENCES `categories` (`category_id`)
) ENGINE=InnoDB DEFAULT CHARSET=utf8;
 
 
CREATE TABLE IF NOT EXISTS `storages` (
  `storage_id` INT(11) NOT NULL AUTO_INCREMENT,
  `storage_name` VARCHAR(30) NOT NULL DEFAULT '0',
  PRIMARY KEY (`storage_id`)
) ENGINE=InnoDB DEFAULT CHARSET=utf8;
 
 
CREATE TABLE IF NOT EXISTS `storage_spares` (
  `storage_id` INT(11) NOT NULL,
  `spares_id` INT(11) NOT NULL,
  `quantity` DOUBLE DEFAULT NULL,
  PRIMARY KEY (`storage_id`,`spares_id`),
  KEY `spares_id` (`spares_id`),
  CONSTRAINT `FK_storage_spares_spares` FOREIGN KEY (`spares_id`) REFERENCES `spares` (`spares_id`) ON DELETE CASCADE,
  CONSTRAINT `FK_storage_spares_storages` FOREIGN KEY (`storage_id`) REFERENCES `storages` (`storage_id`) ON DELETE CASCADE
) ENGINE=InnoDB DEFAULT CHARSET=utf8;
 
CREATE TABLE IF NOT EXISTS `category_property` (
  `category_id` INT(11) NOT NULL,
  `property_id` INT(11) NOT NULL,
  PRIMARY KEY (`category_id`,`property_id`),
  KEY `property_id` (`property_id`),
  CONSTRAINT `FK_category_property_categories` FOREIGN KEY (`category_id`) REFERENCES `categories` (`category_id`) ON DELETE CASCADE,
  CONSTRAINT `FK_category_property_property` FOREIGN KEY (`property_id`) REFERENCES `property` (`property_id`) ON DELETE CASCADE
) ENGINE=InnoDB DEFAULT CHARSET=utf8;
 
CREATE TABLE IF NOT EXISTS `equipment_spares` (
  `equipment_id` INT(11) NOT NULL,
  `spares_id` INT(11) NOT NULL,
  PRIMARY KEY (`equipment_id`,`spares_id`),
  KEY `spares_id` (`spares_id`),
  CONSTRAINT `equipment_spares_ibfk_1` FOREIGN KEY (`equipment_id`) REFERENCES `equipments` (`equipment_id`),
  CONSTRAINT `equipment_spares_ibfk_2` FOREIGN KEY (`spares_id`) REFERENCES `spares` (`spares_id`)
) ENGINE=InnoDB DEFAULT CHARSET=utf8;
 
INSERT INTO `lines` (`line_id`, `name`) VALUES
    (1, 'Линия 1'),
    (2, 'Линия 2'),
    (3, 'Линия 3');
INSERT INTO `districts` (`district_id`, `name`, `line_id`) VALUES
    (1, 'Участок 1', 1),
    (2, 'Участок 2', 1),
    (3, 'Участок 3', 2);
INSERT INTO `equipments` (`equipment_id`, `name`, `district_id`) VALUES
    (1, 'Оборудование 1', 1),
    (2, 'Оборудование 2', 1),
    (3, 'Оборудование 3', 2);
INSERT INTO `property` (`property_id`, `property_name`) VALUES
    (1, 'шт'),
    (2, 'м');
INSERT INTO `storages` (`storage_id`, `storage_name`) VALUES
    (1, 'Склад 1'),
    (2, 'Склад 2');
INSERT INTO `categories` (`category_id`, `name_category`) VALUES
    (1, 'Категория 1'),
    (2, 'Категория 2'),
    (3, 'Категория 3'),
    (4, 'Категория 4');
INSERT INTO `category_property` (`category_id`, `property_id`) VALUES
    (1, 1),
    (2, 1),
    (3, 1);
INSERT INTO `spares` (`spares_id`, `material`, `description`, `price`, `quantity`, `category_id`) VALUES
    (1, 'сталь', 'деталь 111', 0, 2, 3),
    (2, 'сталь', 'деталь 122', 10, 4, 3);
INSERT INTO `storage_spares` (`storage_id`, `spares_id`, `quantity`) VALUES
    (1, 1, 12),
    (1, 2, 2),
    (2, 1, 5);