flask建表遇到的错误： flask,sqlalchemy.exc.OperationalError: (MySQLdb._exceptions.OperationalError) (1071, 'Specified key was too long; max key length is 767 bytes')

error:flask,sqlalchemy.exc.OperationalError: (MySQLdb._exceptions.OperationalError) (1071, 'Specified key was too long; max key length is 767 bytes') 

分析：数据库类型字符不对（默认ｌａｔｉｎ）

解决：ALTER DATABASE `databasename` CHARACTER SET utf8;