المشكلة هي عند محاولتي عمل connect لل DATABASE بـ
SQLPLUS / AS SYSDBA:

oracle not avialable
shared memory realm does not exit

وحاولت عمل startup للdatabase
ولكني تعطني الرسالة :
Not connected to oracle

Dear Bro
please send me the error numbers and when it happened?after restart or changing parameters or reg keys..

شكراً للإهتمام رقم الخطأ ORA-27101
ويحدث عندما احاول connect بأي user

ORACLE_HOME or ORACLE_SID is not set properly
when it is not pointing to the right ORACLE_SID, oracle used to give an error
of ORA-01034 .with error of ORA-27101.

Make sure ORACLE_HOME is entered correctly and with no trailing slash.

Example:

$ echo $ORACLE_HOME
$ /app/oracle/817/ << Incorrect

$ echo $ORACLE_HOME
$ /app/oracle/817 << Correct

Make sure the case of ORACLE_SID is correct

Example:

$ echo $ORACLE_SID
$ ora817

$ ps -ef | grep smon
ora_smon_ORA817

Once this has been done, invoke SQL*Plus again.