How do i put my database in archivelog?

Proceed as follows.


SQL*Plus: Release 10.2.0.1.0 - Production on Fri Jul 13 14:50:13 2007

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SQL> conn sys as sysdba
Enter password:
Connected.
SQL> select name,open_mode from v$database;

NAME OPEN_MODE
--------- ----------
XE READ WRITE

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

Total System Global Area 146800640 bytes
Fixed Size 1286220 bytes
Variable Size 71307188 bytes
Database Buffers 71303168 bytes
Redo Buffers 2904064 bytes
Database mounted.
SQL> alter database archivelog;

Database altered.

SQL> alter database open;

Database altered.

SQL> select open_mode,log_mode from v$database;

OPEN_MODE LOG_MODE
---------- ------------
READ WRITE ARCHIVELOG

SQL>