diff --git a/sql/inv.sql b/sql/inv.sql
index 2f02d72..9287936 100644
--- a/sql/inv.sql
+++ b/sql/inv.sql
@@ -1,22 +1,22 @@
 CREATE TABLE `item` (
-	`id` INT(11) NOT NULL AUTO_INCREMENT,
+	`sku` VARCHAR(60) NOT NULL,
 	`name` LONGTEXT DEFAULT NULL,
-	PRIMARY KEY (`id`)
+	PRIMARY KEY (`sku`)
 ) ENGINE=InnoDB DEFAULT CHARSET=utf8mb4;
 
 -- Reselling item price, not including production item price, service item price, and subscription item price
 CREATE TABLE `item_price` (
 	`id` INT(11) NOT NULL AUTO_INCREMENT,
-	`item` INT(11) NOT NULL,
+	`sku` VARCHAR(60) NOT NULL,
 	`type` VARCHAR(4) NOT NULL, -- buy, sell
 	`currency` VARCHAR(3) NOT NULL,
 	`value` INT(11) NOT NULL,
 	`periods` DATETIME NOT NULL,
 	PRIMARY KEY (`id`),
-	KEY `item` (`item`),
-	CONSTRAINT `item_price_fk_item`
-		FOREIGN KEY (`item`)
-		REFERENCES `item`(`id`)
+	KEY `sku` (`sku`),
+	CONSTRAINT `item_price_fk_sku`
+		FOREIGN KEY (`sku`)
+		REFERENCES `item`(`sku`)
 		ON UPDATE CASCADE
 		ON DELETE CASCADE
 ) ENGINE=InnoDB DEFAULT CHARSET=utf8mb4;
@@ -24,15 +24,15 @@ CREATE TABLE `item_price` (
 -- Not including assets inventory, get from buying/production, and shipping/expedition
 CREATE TABLE `inventory` (
 	`id` INT(11) NOT NULL AUTO_INCREMENT,
-	`item` INT(11) NOT NULL,
-	`flow` VARCHAR(20) NOT NULL, -- in, out, buy, sell, buy return, sell return
+	`sku` VARCHAR(60) NOT NULL,
+	`flow` VARCHAR(20) NOT NULL, -- in, out, buy, sell, buy return, sell return, use, produce
 	`when` DATETIME NOT NULL,
 	`qty` INT(11) NOT NULL,
 	`note` LONGTEXT DEFAULT NULL,
 	PRIMARY KEY (`id`),
-	KEY `item` (`item`),
-	CONSTRAINT `inventory_fk_item`
-		FOREIGN KEY (`item`)
-		REFERENCES `item`(`id`)
+	KEY `sku` (`sku`),
+	CONSTRAINT `inventory_fk_sku`
+		FOREIGN KEY (`sku`)
+		REFERENCES `item`(`sku`)
 ) ENGINE=InnoDB DEFAULT CHARSET=utf8mb4;
 -- get from: buying/production