sql alter add column foreign key code example
Example 1: sql foreign key
CREATE TABLE users(
userId INT NOT NULL,
username VARCHAR(64) NOT NULL,
passwd VARCHAR(32) NOT NULL,
PRIMARY KEY(userId);
);
INSERT INTO users VALUES(1000,"Terry","Teabagface$2");
CREATE TABLE orders(
orderId INT NOT NULL,
orderDescription VARCHAR(255),
ordererId INT NOT NULL,
PRIMARY KEY(orderId),
FOREIGN KEY (ordererId) REFERENCES users(userId)
);
INSERT INTO orders VALUES(0001,"Goat p0rn Weekly",1000);
Example 2: add new column in sql with foreign key
ALTER TABLE `fb_banners`
ADD `city_id` BIGINT(20) UNSIGNED NULL DEFAULT NULL AFTER `BannerID`,
ADD INDEX `Foreign_city_id_banners` (`city_id`) USING BTREE,
ADD CONSTRAINT `Foreign_city_id_banners` FOREIGN KEY (`city_id`) REFERENCES `foodsafari`.`fb_cities` (`id`) ON UPDATE CASCADE ON DELETE CASCADE;