insert a foreign key in mysql code example
Example 1: alter table add foreign key mysql
ALTER TABLE orders
ADD
FOREIGN KEY (user_id) REFERENCES users(id) ON DELETE CASCADE;
Example 2: how to connect database foreign key in mysql
CREATE TABLE products(
productId INT AUTO_INCREMENT PRIMARY KEY,
productName varchar(100) not null,
categoryId INT NOT NULL,
CONSTRAINT fk_category
FOREIGN KEY (categoryId)
REFERENCES categories(categoryId)
ON UPDATE CASCADE
ON DELETE CASCADE
) ENGINE=INNODB;