Start the oracle database, close the connection

Log database

method one:

$ sqlplus / as sysdba

[oracle@dev /]$ sqlplus / as sysdba

SQL*Plus: Release 11.2.0.1.0 Production on Fri May 31 09:34:26 2019

Copyright (c) 1982, 2009, Oracle.  All rights reserved.


Connected to:
Oracle Database 11g Enterprise Edition Release 11.2.0.1.0 - 64bit Production
With the Partitioning, OLAP, Data Mining and Real Application Testing options

SQL>

Method Two:

$ sqlplus /nolog

SQL> conn /as sysdba

[oracle@dev ~]$ sqlplus /nolog

SQL*Plus: Release 11.2.0.1.0 Production on Fri May 31 17:05:28 2019

Copyright (c) 1982, 2009, Oracle.  All rights reserved.

SQL>
SQL> conn /as sysdba
Connected.
SQL>
SQL>

Close the database

SQL> shutdown immediate;

SQL> shutdown immediate;
Database closed.
Database dismounted.
ORACLE instance shut down.

Load start the database to mount state

SQL> startup mount

SQL> startup mount
ORACLE instance started.

Total System Global Area 1603411968 bytes
Fixed Size                  2213776 bytes
Variable Size             402655344 bytes
Database Buffers         1191182336 bytes
Redo Buffers                7360512 bytes
Database mounted.

Start the database

SQL> startup

SQL> startup
ORACLE instance started.

Total System Global Area 1603411968 bytes
Fixed Size                  2213776 bytes
Variable Size             402655344 bytes
Database Buffers         1191182336 bytes
Redo Buffers                7360512 bytes
Database mounted.
Database opened.

end