Скачать с ютуб MySQL: FOREIGN KEYS are easy (kind of) в хорошем качестве

MySQL: FOREIGN KEYS are easy (kind of)

#MySQL #course #tutorial 00:00:00 intro 00:00:50 CREATE TABLE customers 00:01:17 INSERT INTO customers 00:01:58 CREATE TABLE transactions w/ FOREIGN KEY 00:02:20 Add FOREIGN KEY to a new table 00:03:34 DROP FOREIGN KEY 00:04:07 ADD a named FOREIGN KEY to an existing table 00:05:28 re-populating our transactions table 00:05:45 AUTO_INCREMENT transactions 00:06:05 inserting new rows into transactions 00:07:21 attempting to delete a referenced primary key 00:07:53 conclusion CREATE TABLE customers ( customer_id INT PRIMARY KEY AUTO_INCREMENT, first_name VARCHAR(50), last_name VARCHAR(50) ); INSERT INTO customers (first_name, last_name) VALUES ("Fred", "Fish"), ("Larry", "Lobster"), ("Bubble", "Bass"); SELECT * FROM customers; -- Add a named foreign key constraint to a new table CREATE TABLE transactions ( transaction_id INT PRIMARY KEY AUTO_INCREMENT, amount DECIMAL(5, 2), customer_id INT, FOREIGN KEY (customer_id) REFERENCES customers(customer_id) ); ALTER TABLE transactions AUTO_INCREMENT = 1000; -- Add a named foreign key constraint to an existing table ALTER TABLE customers ADD CONSTRAINT fk_customer_id FOREIGN KEY (customer_id) REFERENCES customers(customer_id);