ORA-12523: TNS: 监听程序无法找到适用于客户机连接的例程
------解决思路----------------------
1、先确认服务和监听起来了没
2、测试一下本机能访问吗
3、TNSPING 服务名 如果不通检查服务名的参数配置
4、用PL或SQLPLUS链接
------解决思路----------------------
tnsping能ping通，那就应该是监听的问题了
lsnrctl status查看监听状态
------解决思路----------------------
12523, 00000, "TNS:listener could not find instance appropriate for the client connection"
// *Cause: The listener could not find any available (database) instances,
// that are appropriate for the client connection.
// *Action: Run "lsnrctl services" to ensure that the instance(s) are
// registered with the listener, and have status READY.
运行lsnrctl services 看看isntance的服务是否已经注册。
看看isntance是否已经启动，如果已经启动，还没有注册
可以试试alter system register 注册试试。