ORA-12505

oracle 数据库，用sqldeveloper 打开报了
ORA-12505: TNS:listener does not currently know of SID given in connect descriptor；

1. 先通过sqlplus\命令行, 查看当前正在使用的数据库实例及主机名
   SQL>conn/as sysdba
   SQL>select instance_name from v$instance;

SQL>select host_name from v$instance;
如图所示

2. 再打开oracle安装路径下的listener.ora文件
   红色部分是修改内容

重新启动TNSListener ，这样就可以用sql developer连接数据库实例了

ps：如果知道数据库实例的用户名和密码，可以直接sql plus登陆并获取数据库SID 值
注：oracle官网给出的提示
ORA-12505: TNS:listener does not currently know of SID given in connect descriptor
Cause: The listener received a request to establish a connection to a database or other service. The connect descriptor received by the listener specified a SID for an instance (usually a database instance) that either has not yet dynamically registered with the listener or has not been statically configured for the listener. This may be a temporary condition such as after the listener has started, but before the database instance has registered with the listener.

Action: - Wait a moment and try to connect a second time. - Check which instances are currently known by the listener by executing: lsnrctl services listener name - Check that the SID parameter in the connect descriptor specifies an instance known by the listener. - Check for an event in the listener.log file.