What to do if I cannot connect database as sys as sqlplus as sysdba?
I am new to oracle server 18c (currently taking an online course). My problem is sql*plus where I tried to use sqlplus then sys as sysdba (it did not work) and the error appeared below.
However, if I use sqlplus / as sysdba (it worked, and I don't know why)
I have tried this command: lsnrctl start, but again not working. In addition, I have checked my listener.ora and tnsnames.oraca
I have attached my environment set up in .bash_profile
If the password contains special characters such as @, enter the password between double quotes:
$ sqlplus as sysdba
SQL*Plus: Release 19.0.0.0.0 - Production on Mon Nov 11 15:41:40 2019
Version 19.5.0.0.0
Copyright (c) 1982, 2019, Oracle. All rights reserved.
Connected to:
Oracle Database 19c Enterprise Edition Release 19.0.0.0.0 - Production
Version 19.5.0.0.0
SQL> connect sys/a@abcd as sysdba
ERROR:
ORA-12154: TNS:could not resolve the connect identifier specified
Warning: You are no longer connected to ORACLE.
SQL> connect sys/"a@abcd" as sysdba
Connected.
SQL>