feat(task.sql): implement data normalization

task.sql

@@ -1,33 +1,50 @@
--- Create database and tables
-
+-- Recreate database
+DROP DATABASE IF EXISTS ShopDB;
 CREATE DATABASE ShopDB;
 USE ShopDB;
 
 CREATE TABLE Countries (
-    ID INT,
-    Name VARCHAR(50),
-    PRIMARY KEY (ID)
+    ID INT PRIMARY KEY,
+    Name VARCHAR(50)
 );
 
-CREATE TABLE ProductInventory (
-    ID INT,
-    ProductName VARCHAR(50),
-    WarehouseAmount INT,
+CREATE TABLE Products (
+    ID INT PRIMARY KEY,
+    ProductName VARCHAR(50)
+);
+
+CREATE TABLE Warehouses (
+    ID INT PRIMARY KEY,
     WarehouseName VARCHAR(50),
-    WarehouseAddress VARCHAR(50), 
+    WarehouseAddress VARCHAR(50),
     CountryID INT,
-	FOREIGN KEY (CountryID) REFERENCES Countries(ID) ON DELETE NO ACTION,
-    PRIMARY KEY (ID)
+    FOREIGN KEY (CountryID) REFERENCES Countries(ID)
+);
+
+CREATE TABLE ProductInventory (
+    ID INT PRIMARY KEY,
+    ProductID INT,
+    WarehouseAmount INT,
+    WarehouseID INT,
+    FOREIGN KEY (ProductID) REFERENCES Products(ID),
+    FOREIGN KEY (WarehouseID) REFERENCES Warehouses(ID)
 );
 
 -- Populate test data
 
-INSERT INTO Countries (ID,Name)
-	VALUES (1, 'Country1');
-INSERT INTO Countries (ID,Name)
-	VALUES (2, 'Country2');
-
-INSERT INTO ProductInventory (ID,ProductName,WarehouseAmount,WarehouseName,WarehouseAddress,CountryID)
-	VALUES (1, 'AwersomeProduct', 2, 'Warehouse-1', 'City-1, Street-1',1);
-INSERT INTO ProductInventory (ID,ProductName,WarehouseAmount,WarehouseName,WarehouseAddress,CountryID)
-	VALUES (2, 'AwersomeProduct', 5, 'Warehouse-2', 'City-2, Street-2',2);
+-- Countries
+INSERT INTO Countries VALUES (1, 'Country1');
+INSERT INTO Countries VALUES (2, 'Country2');
+
+-- Products
+INSERT INTO Products VALUES (1, 'AwersomeProduct');
+
+-- Warehouses
+INSERT INTO Warehouses VALUES
+(1, 'Warehouse-1', 'City-1, Street-1', 1),
+(2, 'Warehouse-2', 'City-2, Street-2', 2);
+
+-- ProductInventory
+INSERT INTO ProductInventory VALUES
+(1, 1, 2, 1),
+(2, 1, 5, 2);