In oracle database 11g you can alter individual tables
to be read only. When in read-only mode, you canít
issue any DML statements against the table.

SQL>alter table emp read only;

Table altered.

SQL> select table_name,read_only from user_tables
2 where table_name='EMP';

Code:
TABLE_NAME  READ_ONLY
----------- ---------
EMP         YES
SQL>alter table emp read write;

Table altered.


SQL> select table_name,read_only from user_tables
2 where table_name='EMP';


Code:
TABLE_NAME  READ_ONLY
----------- ---------
EMP         NO