scott@9i > alter table dept disable table lock;

Table altered.

scott@9i > truncate table dept;
truncate table dept
               *
ERROR at line 1:
ORA-00069: cannot acquire lock -- table locks disabled for DEPT


scott@9i > alter table dept add (c1 number);
alter table dept add (c1 number)
*
ERROR at line 1:
ORA-00069: cannot acquire lock -- table locks disabled for DEPT


scott@9i > delete from dept;

4 rows deleted.