查看mysql数据库错误码（error code）的三个方法：
◆1. MySQL Reference Manual有Appendix B. Error Codes and Messages
◆2. 查看页面：https://dev.mysql.com/doc/refman/5.0/en/error-handling.html
◆3. MySQL的bin目录下提供了perror.exe工具，使用方法如下：
# /usr/local/mysql/bin/perror 10
Error code 10: No child processes
# /usr/local/mysql/bin/perror 127
Error code 127: Network is down
127 = Record-file is crashed
# /usr/local/mysql/bin/perror 134
Error code 134: Transport endpoint is not connected
134 = Record was already deleted (or record file crashed)