SHOW DATABASE –显示当前的数据库

CREATE DATABASE XXX –创建数据库

DEFAULT CHARACTER SET utf8mb4
DEFAULT COLLATE utf8mb4_unicode_ci;

USE XXX;

CREATE TABLE IF NOT EXISTS airline( –创建数据表
code char(3) PRIMARY KEY,
airlinename varchar(1024)
);

ALTER TABLE S

ADD FOREIGN KEY (a) REFERENCES E(a),
ADD FOREIGN KEY (c) REFERENCES  F(c);