Question

write a procedure that includes two sql statements coded as a transaction to delete the row with a customer id of 8 from the customers table. to do this, you must first delete all addresses for that customer from the addresses table. you must also delete the orders for the customer which means first deleting the order items

Answer 1

To delete a customer from the customers table in SQL as part of a transaction, steps include starting the transaction, deleting related addresses, order items, and orders, before removing the customer entry, and then committing the transaction.

Step-by-step explanation:

To delete a customer with a specific ID from the customers table in SQL, a transaction consisting of multiple statements that remove records from related tables first is required. Following is a procedure for deleting a customer with a customer ID of 8:

1. Start the transaction to ensure that all the following operations are treated as a single unit of work.
2. Delete all addresses for the customer from the addresses table.
3. Delete all order items related to the customer's orders from the order items table.
4. Delete all orders for the customer from the orders table.
5. Delete the customer from the customers table.
6. Commit the transaction to make all changes permanent in the database if all the statements are executed successfully.

Below is an example of the SQL code for this procedure:

BEGIN TRANSACTION;

DELETE FROM order_items
WHERE order_id IN (
SELECT order_id FROM orders WHERE customer_id = 8
);

DELETE FROM orders
WHERE customer_id = 8;

DELETE FROM addresses
WHERE customer_id = 8;

DELETE FROM customers
WHERE customer_id = 8;

COMMIT;

If any step fails, make sure to rollback the transaction to avoid leaving the database in an inconsistent state.