Solution

task.sql

@@ -4,30 +4,48 @@ CREATE DATABASE ShopDB;
 USE ShopDB;
 
 CREATE TABLE Countries (
-    ID INT,
-    Name VARCHAR(50),
-    PRIMARY KEY (ID)
+    ID INT AUTO_INCREMENT PRIMARY KEY,
+    Name VARCHAR(50) NOT NULL
 );
 
-CREATE TABLE ProductInventory (
-    ID INT,
-    ProductName VARCHAR(50),
-    WarehouseAmount INT,
-    WarehouseName VARCHAR(50),
-    WarehouseAddress VARCHAR(50), 
-    CountryID INT,
-	FOREIGN KEY (CountryID) REFERENCES Countries(ID) ON DELETE NO ACTION,
-    PRIMARY KEY (ID)
+CREATE TABLE Products (
+    ID INT AUTO_INCREMENT PRIMARY KEY,
+    Name VARCHAR(50) NOT NULL
+);
+
+CREATE TABLE Warehouses (
+    ID INT AUTO_INCREMENT PRIMARY KEY,
+    Name VARCHAR(50) NOT NULL,
+    Address VARCHAR(100) NOT NULL,
+    CountryID INT NOT NULL,
+    FOREIGN KEY (CountryID) REFERENCES Countries(ID)
+        ON DELETE RESTRICT
+);
+
+CREATE TABLE Inventory (
+    ProductID INT NOT NULL,
+    WarehouseID INT NOT NULL,
+    Amount INT NOT NULL,
+    PRIMARY KEY (ProductID, WarehouseID),
+    FOREIGN KEY (ProductID) REFERENCES Products(ID)
+        ON DELETE CASCADE,
+    FOREIGN KEY (WarehouseID) REFERENCES Warehouses(ID)
+        ON DELETE CASCADE
 );
 
 -- 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);
+INSERT INTO Countries (Name) VALUES
+    ('Country1'),
+    ('Country2');
+
+INSERT INTO Products (Name) VALUES
+    ('AwesomeProduct');
+
+INSERT INTO Warehouses (Name, Address, CountryID) VALUES
+    ('Warehouse-1', 'City-1, Street-1', 1),
+    ('Warehouse-2', 'City-2, Street-2', 2);
+
+INSERT INTO Inventory (ProductID, WarehouseID, Amount) VALUES
+    (1, 1, 2),
+    (1, 2, 5);