ORA-01507
database not mounted
Cause
A command was attempted that requires the database to be mounted.
Action
If you are using the ALTER DATABASE statement via the SQLDBA startup command, specify the MOUNT option to startup; else if you are directly doing an ALTER DATABASE DISMOUNT, do nothing; else specify the MOUNT option to ALTER DATABASE. If you are doing a backup or copy, you must first mount the desired database. If you are doing a FLASHBACK DATABASE, you must first mount the desired database.