How To Bring a Tablespace Offline?

If you want to stop users using a tablespace, you can bring it offline using the ALTER TABLESPACE ... OFFLINE statement as shown in the following script:
SQL> alter tablespace abdulwasiq offline normal;

Tablespace altered.
SQL> select TABLESPACE_NAME,STATUS from dba_tablespaces;

TABLESPACE_NAME                STATUS
------------------------------ ---------
SYSTEM                         ONLINE
SYSAUX                         ONLINE
UNDOTBS1                       ONLINE
TEMP                           ONLINE
USERS                          ONLINE
EXAMPLE                        ONLINE
ABDULWASIQ                     OFFLINE
MYTBS                          ONLINE

8 rows selected.

SQL>