c# 连接 mysql数据库 弹出异常 Unknown system variable 'lower_case_table_names'

visual studio 2019

c# nuget mysql.data package from oracle

when  connection open

throw exception 'Unknown system variable 'lower_case_table_names'

 本地mysql版本5.0.22

mysql> select version();
+---------------------+
| version()           |
+---------------------+
| 5.0.22-community-nt |
+---------------------+
1 row in set (0.00 sec)

在navicat 中查询

select @@lower_case_table_names;

结果

[SQL] select @@lower_case_table_names;
[Err] 1193 - Unknown system variable 'lower_case_table_names'

看来是MySQL.data.dll提供的api 在使用之前需要查询MySQL设置lower_case_table_names，但是找不到，因此引起异常

【解决1】

在MySQL服务中加入该变量的设置

并重启

mysql> show variables;

 low_priority_updates            | OFF                                                             |
| lower_case_file_system          | OFF                                                             |
| lower_case_table_names          | 1                                                               |
| max_allowed_packet              | 1048576                                                         |
| max_binlog_cache_size           | 4294967295                                                      |
| max_binlog_size                 | 1073741824                                                      |

变量存在，但是——————————》

mysql> select @@lower_case_table_names
    -> ;
ERROR 1193 (HY000): Unknown system variable 'lower_case_table_names'

【无效】

【解决2】

升级MySQL

mysql> select version();
+------------+
| version()  |
+------------+
| 5.7.28-log |
+------------+
1 row in set (0.00 sec)

mysql> select @@lower_case_table_names;
+--------------------------+
| @@lower_case_table_names |
+--------------------------+
|                        1 |
+--------------------------+
1 row in set (0.00 sec)

【问题解决！】