more pieces of the puzzle

back to noodling around with the item table. i think i am going to try and be a bit less deliberative with all of this, since i clearly don’t have a lot of spare time to spend on this and need to build some momentum.

i won’t get into tracking inventory yet, but a basic quality of an item i want to track is a minimum quantity to have on hand. i guess in an ideal system, these minimum quantities would be dynamic and driven by actual sales data, but for now we’ll be hand-tuning this number for items.

an item gets called by its name, so we’ll need a field for that.

so here is our final rough draft of the item table:

CREATE TABLE `item` (
  `id` int(10) unsigned NOT NULL AUTO_INCREMENT,
  `code` varchar(255) NOT NULL,
  `name` varchar(255) NOT NULL,
  `brand` int(10) unsigned DEFAULT NULL,
  `retail_price` decimal(9,2) NOT NULL,
  `discount_type` enum('percentage','relative','fixed') DEFAULT NULL,
  `discount` decimal(9,2) DEFAULT NULL,
  `minimum_quantity` int(10) unsigned NOT NULL,
  PRIMARY KEY (`id`),
  UNIQUE KEY `code` (`code`)
)

and you’ll notice that i snuck in a brand column there, which will be our link over to another table, very basic for now (and maybe for good):

CREATE TABLE `brand` (
  `id` int(10) unsigned NOT NULL,
  `name` varchar(255) NOT NULL,
  PRIMARY KEY (`id`)
)

we have a nice barcode scanner that we’d like to keep using, so we’ll need to have barcodes we can relate to items. but some items have more than one barcode (common with books that have an ISBN and a UPC), and sometimes things come in packages of one quantity of items that can be decomposed into individual items with different barcodes. so barcodes will live in their own table, and each code will identify an item and a quantity:

CREATE TABLE `barcode` (
  `code` varchar(255) NOT NULL,
  `item` int(10) unsigned NOT NULL,
  `quantity` int(10) unsigned NOT NULL DEFAULT '1',
  PRIMARY KEY (`code`),
  KEY `item` (`item`)
)

we’ll want some more categorization later, but it’s not critical yet. inventory is next, but i am going to have to sleep on it.