1. First We need to set the environment path for PATH,ORACLE_HOME and ORACLE_SID. we can get the path of sid from services.msc

C:\Windows\system32>set PATH=f:\app\ankush\product\12.1.0\dbhome_4\bin

C:\Windows\system32>set ORACLE_HOME=f:\app\ankush\product\12.1.0\dbhome_4\

C:\Windows\system32>set ORACLE_SID=GRP

2. Connect to sqlplus utility and fire the startup command.

C:\Windows\system32>sqlplus / as sysdba

SQL*Plus: Release 12.1.0.2.0 Production on Tue Oct 30 00:20:10 2018

Connected to an idle instance.

SQL> startup

ORACLE instance started.

Total System Global Area 3841982464 bytes

Fixed Size 3052576 bytes

Variable Size 872418272 bytes

Database Buffers 2952790016 bytes

Redo Buffers 13721600 bytes

Database mounted.

Database opened.

3. At last check the status of database.

SQL> select name,open_mode from v$database;

NAME OPEN_MODE

——— ——————–

GRP READ WRITE