Restart after installing ORACLE under Linux cannot log on to the database ora-01034:oracle not available

Linux installed the database, after the installation can be used, today, the launch will not be able to use, prompted Oracle not available, and later find information, it is said that the Oracle service is not open. The problem can be solved in the following way.

[[Email protected]~]$ su-oracle

[[Email protected]~]$ sqlplus

Connected to an idle instance.

Enter Username:/as SYSDBA

Sql>startup------------------start a DB instance
Oracle instance started.
Total System Global Area *****bytes
Fixed Size *****bytes
Variable Size *****bytes
Database buffers *****bytes
Redo buffers *****bytes
Database mounted.
Database opened.

It's going to work.

Restart after installing ORACLE under Linux cannot log on to the database ora-01034:oracle not available