问errno: 150“外键约束格式不正确”

EN

-- Setup my members database
DROP DATABASE IF EXISTS mymembers;
CREATE DATABASE IF NOT EXISTS mymembers;

/*
* The list of all members in the community
*/
DROP TABLE IF EXISTS members;
CREATE TABLE members
(
id INT NOT NULL AUTO_INCREMENT,
name VARCHAR(30),
steamID3 INT NOT NULL UNIQUE,
PRIMARY KEY (id)
);

/*
* Lists all servers in operation
*/
DROP TABLE IF EXISTS servers;
CREATE TABLE servers
(
sid INT NOT NULL AUTO_INCREMENT,
sname VARCHAR(30), -- name of server (short name)
PRIMARY KEY(sid)
);

/*
* Maps a member and a server together along with a flag. 
* Record (0, 12, 1, 0) indicates member 12 has flag 0 on server 1.
*/
DROP TABLE IF EXISTS serverPermissions;
CREATE TABLE serverPermissions
(
mid INT,
sid INT,
flagid INT,
PRIMARY KEY(mid, sid, flagid),
FOREIGN KEY (mid) REFERENCES members(id),
FOREIGN KEY (sid) REFERENCES servers(sid),
FOREIGN KEY (flagid) REFERENCES flags(id)
);

/*
* flags are used to give custom permissions to players.
* For example a record may be: (0, "VIP", "This play is very important")
*/
DROP TABLE IF EXISTS flags;
CREATE TABLE flags
(
id INT NOT NULL AUTO_INCREMENT,
name VARCHAR(10),
description VARCHAR(100),
PRIMARY KEY(id)
);