Databases/transactions

databases/transactions/transactions.sql

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+/* INSERT: Add cart with orders */
+begin;
+	savepoint S1;
+	insert into carts values(9999, 40, 440, 500, now());
+	insert into orders values(9999, 9999, 1, 60, 500, now(), now());
+
+	savepoint S2;
+	insert into carts values(99990, 30, 540, 600, now());
+	insert into orders values(99990, 99990, 2, 60, 540, now(), now());
+	-- undo inserts after S2
+	rollback to savepoint S2;
+commit;
+
+
+/* DELETE: Full delition of customer, including carts and orders */
+begin;
+
+	-- Delete orders for user_id
+	delete from orders 
+	where carts_cart_id in (
+		-- In case if users has more than 1 cart
+		select cart_id from carts 
+		where users_user_id = 20
+);
+
+	-- Delete user by user_id 
+	delete from users 
+	where user_id = 20;
+
+	-- Delete carts for user_id
+	delete from carts 
+	where users_user_id = 20;
+
+commit;
+
+
+/* UPDATE: Rise product price by 10% and update total, subtotal in Carts 
+ * and total in Orders for unpaid orders (status 1 and 2) */
+begin;
+	-- Raise price of product by 10%
+	update products
+	set price = price * 1.1;
+
+
+	-- Update total and subtotal in carts
+	update carts as c
+	set total = (
+		select sum(price)
+		from products p join cart_product cp
+		on cp.products_product_id = p.product_id 
+		join carts c1
+		on c1.cart_id = cp.carts_cart_id
+		where c.cart_id = c1.cart_id 
+);
+	update carts as c 
+	set subtotal = total;
+
+
+	-- Update orders using carts 
+	update orders as o
+	set total = (
+		select sum(c.total)
+		from orders o1 join carts c
+		on o1.carts_cart_id = c.cart_id
+		where o1.order_id = o.order_id 
+	);
+commit;