Oracle connection error -- Connected to an idle instance solved

Oracle connection error-Connected to an idle instance solution symptom and solution: phenomenon: www.2cto.com PL/SQL Developer cannot connect to the database instance, prompting no listening SID. Use sysdba to log on and prompt Connected to an idle instance. Method 1: restart the oracle command in linux (if this service is not available, use idea 2) restart the oracle service: service oracle restart, view the oracle status: service oracle status. View oracle instance: echo $ ORALCE_SID result: the Retry is invalid. Method 2: Go to sqlplus to shutdown the database and start startup. SQL> conn/as sysdba Connected to an idle instance after Query Information: Start the oracle service under sqlplu and switch to the user instance test. Oracle $ sqlplus "/as sysdba" Connected to an idle instance. SQL> startup output prompt information. This is normal. You can use the select * from dba_users; statement for verification.