ORACLE Error - ORA-01034 & ORA-27101

Error : ORA-01034: ORACLE not available
       ORA-27101: shared memory realm does not exist

Cause: This error shown while connected to oracle schema,because of Oracle service is running but database is not opened.

Solution -> connect to oracle schema and startup database
 sql>sys/password as sysdba
 sql>startup

SP2-0110: Cannot create save file "afiedt.buf"

This error is most general error, everybody face this error either he is a student or trainee or experienced. Most of trainee starts from oracle and we generally used the SQL CMD to write the commands and execute the command. The feature of SQL CMD is that we can re-edit the SQL if it is not executed well, to use this feature we need to assign a buffer file where it can save the the previous execution history.

Error
SP2-0110: Cannot create save file "afiedt.buf"

SOLUTION-

1.Open CMD
2.set editor=notepad
3.open sqlplus and login with user

4.Thats it.

ORA-28056: Writing audit rec .... solved

ORA-28056: Writing audit records to Windows Event Log failed Error



Error faced during login user

SQL> conn scott/tiger
ERROR:
ORA-28056: Writing audit records to Windows Event Log failed
ORA-01031: insufficient privileges

solution
This was because the Event Viewer log is full and unable to log events.We need to clear the event log as follows Control Panel->Administrative Tools->Event Viewer->Clear All Events

picture can vary syatem to system

this is worked for me