mysql外键表insert

-- 创建主键表
CREATE TABLE users (
    id INT PRIMARY KEY AUTO_INCREMENT,
    name VARCHAR(255) NOT NULL
);

-- 创建外键表
CREATE TABLE orders (
    id INT PRIMARY KEY AUTO_INCREMENT,
    user_id INT,
    amount DECIMAL(10, 2),
    FOREIGN KEY (user_id) REFERENCES users(id) ON DELETE CASCADE
);

-- 插入主键表数据
INSERT INTO users (name) VALUES ('Alice');
INSERT INTO users (name) VALUES ('Bob');

-- 插入外键表数据
INSERT INTO orders (user_id, amount) VALUES (1, 100.00);
INSERT INTO orders (user_id, amount) VALUES (2, 200.00);

-- 确保主键表中有对应的数据
INSERT INTO users (name) VALUES ('Charlie');

-- 再插入外键表数据
INSERT INTO orders (user_id, amount) VALUES (3, 300.00);

-- 删除外键表数据
DELETE FROM orders WHERE user_id = 1;

-- 删除主键表数据
DELETE FROM users WHERE id = 1;

CREATE TABLE orders (
    id INT PRIMARY KEY AUTO_INCREMENT,
    user_id INT,
    amount DECIMAL(10, 2),
    FOREIGN KEY (user_id) REFERENCES users(id) ON DELETE CASCADE
);