articleID 长度是255*4 > 767 的
MySQL has a prefix limitation of 767 bytes in InnoDB, and 1000 bytes in MyISAM. This has never been a problem for me, until I started using UTF-16 as the character set for one of my databases. UTF-16 can use up to 4 bytes per character which means that in an InnoDB table, you can’t have any keys longer than 191 characters. Take this CREATE statement for example:
id int(11) NOT NULL AUTO_INCREMENT,
username varchar(32) NOT NULL,
password varchar(64) NOT NULL,
PRIMARY KEY (
) ENGINE=InnoDB DEFAULT CHARSET=utf16 AUTO_INCREMENT=1 ;
This will fail with an error like Specified key was too long; max key length is 767 bytes, because the UNIQUE INDEX on the email field requires at least 1020 bytes (255 * 4).