ORA-01034 ORACLE not available

Cause: Oracle was not started. Possible causes include the following:

The SGA requires more space than was allocated for it.
The operating-system variable pointing to the instance is improperly defined.

Action: Refer to accompanying messages for possible causes and correct the problem mentioned in the other messages. If Oracle has been initialized, then on some operating systems, verify that Oracle was linked correctly. See the platform-specific Oracle documentation.