SQL> create tablespace deni datafile 'c:\deni01.dbf' size 3m;

Tablespace created.

SQL> create user deniusr identified by deni default tablespace deni quota 2m on
deni;

User created.

SQL> grant connect to deniusr;

Grant succeeded.


SQL> create table deniusr.test as select * from all_objects where rownum <= 100;


Table created.

SQL> alter tablespace deni offline;

Tablespace altered.

SQL> select count(*) from deniusr.test;
select count(*) from deniusr.test
                             *
ERROR at line 1:
ORA-00376: file 8 cannot be read at this time
ORA-01110: data file 8: 'C:\DENI01.DBF'


SQL> truncate table deniusr.test;
truncate table deniusr.test
                       *
ERROR at line 1:
ORA-00376: file 8 cannot be read at this time
ORA-01110: data file 8: 'C:\DENI01.DBF'


SQL> alter tablespace deni online;

Tablespace altered.

SQL> alter tablespace deni read only;

Tablespace altered.

SQL> select count(*) from deniusr.test;

  COUNT(*)
----------
       100

SQL> insert into deniusr.test select * from all_objects where rownum <=10;
insert into deniusr.test select * from all_objects where rownum <=10
                    *
ERROR at line 1:
ORA-00372: file 8 cannot be modified at this time
ORA-01110: data file 8: 'C:\DENI01.DBF'


SQL> truncate table deniusr.test;
truncate table deniusr.test
                       *
ERROR at line 1:
ORA-00372: file 8 cannot be modified at this time
ORA-01110: data file 8: 'C:\DENI01.DBF'


SQL>