Is there a way to enforce the use of sequences

Question

is there a way to stop someone from inserting an id without using the sequence?
CREATE SEQUENCE id_seq
   START WITH 1;
CREATE TABLE test_table (id_seq NUMBER (4) PRIMARY KEY);
INSERT INTO test_table
     VALUES (id_seq.NEXTVAL);
INSERT INTO test_table
     VALUES (2);
INSERT INTO test_table
     VALUES (id_seq.NEXTVAL);gives us
ORA-00001: unique constraint (DSAMSTRC.SYS_C0091648) violated
as it should
however is there a check constraint of some ilk that ensures that the user is using the sequence when doing inserts?
so that the second insert
INSERT INTO test_table
     VALUES (2);gives me some sort of check constraint violation that I'm not using the id_seq.NEXTVAL ?

Answer 1

Justin:
One minor problem with your trigger. If the "bad" insert is the first thing done in the session you get:
SQL> insert into test_table values(25);
insert into test_table values(25)
ERROR at line 1:
ORA-08002: sequence ID_SEQ.CURRVAL is not yet defined in this session
ORA-06512: at "OPS$ORACLE.TRG_TEST_TABLE", line 4
ORA-04088: error during execution of trigger 'OPS$ORACLE.TRG_TEST_TABLE'If you want to raise an exception instead of just silently using the sequence as Frank suggests you need something more like:
create trigger trg_test_table
   before insert on test_table
   for each row
declare
   l_currval integer;
   no_currval exception;
   PRAGMA EXCEPTION_INIT (no_currval, -8002);
begin
   select id_seq.currval
   into l_currval
   from dual;
   if( l_currval != :new.id_seq ) then
      raise_application_error( -20001, 'Hey!  Use the sequence' );
   end if;
exception
   when no_currval then
      raise_application_error( -20001, 'Hey!  Use the sequence' );
end;John