mysql dialect or by jpa.database-platformhibernate.dialect明确指定，也可以不明确指定，而是让hibernate通过所连数据库自己进行判断。
But if you want to explicitly specified, the value specified must match the connected database, you can not specify a value is MySQLDialect, but the database version has more than 5, and this will lead to inconsistent dialects engine and database errors.