Starting up Oracle DB

Often when your DB machine reboots, the DB might not be in an open state and would need to be restarted. This is a very common set of commands that we often forget.
I have added it below for convenience:

>sqlplus /nolog
>connect /as sysdba
>startup

Then at the command prompt:

>lsnrctl start

That should get the DB up and running.

To make sure that your TNS is working from the machine that you want to establish connection, type the following:

>tnsping

it should return OK.

If you want to check as to what the existing TNS names on your machine, look in the following file:

$ORACLE_HOME/network/admin/tnsnames.ora