OS Authentication We usually connect to the database by / AS SYSDBA without providing any password for maintenance works, such as startup, shutdown and backup.… Read More »How to Connect a PDB Directly by OS Authentication
ORA-28002 ORA-28002 means that the password of the user will expire soon in X days, although the user is allowable to connect to the database.… Read More »How to Resolve ORA-28002: the password will expire within days
ORA-01017 ORA-01017 means that you either provided an incorrect pair of username and password, or mismatched authentication protocol, so the database that you tried to… Read More »How to Resolve ORA-01017: invalid username/password; logon denied
32-bit or 64-bit In some situations, we need to know whether our Oracle client is 32-bit or 64-bit in order to use the right tool… Read More »How to Check 32-bit or 64-bit Oracle Client
Connected to an idle instance Actually, Connected to an idle instance is a message rather than an error, it indicates that the database you entered… Read More »How to Resolve "Connected to an idle instance"
ORA-12154 means that your connection tools including sqlplus cannot use TNSNAMES naming method for some reason. This reminds me that there're same error patterns in… Read More »How to Resolve ORA-12154: TNS:could not resolve the connect identifier specified