problem with foreign keys

Hiya, I'm having a prob I'd really appreciate any help. I get the message 'ORA-02273: this unique/primary key is referenced by some foreign keys' every time i try these foreign keys. I read another post on something similar but still need some help.

For example I have 2 tables:

CREATE TABLE EQUIPMENT
(serialno varchar2(7) not null,
equip varchar2(30),
primary key (serialno) );

CREATE TABLE ROOMBOOKING
(bookingdate date not null,
sess char(1) not null,
roomno number(3) not null,
misc varchar2(30),
primary key (bookingdate, sess, roomno) ); <<SO COMPOSITE KEY HERE

Now I need to make foreign keys in another table to some of these columns but I keep getting there error. For example I've got a table called EQUIPMENTBOOKING that contains
sess, bookingdate, roomno, serialno

but I cant get the keys working.

ALTER TABLE EQUIPMENTBOOKING
add constraint fkey_room
foreign key (bookingdate, roomno, sess) references roombooking (bookingdate, roomno, sess) ;

tried one at a time

ALTER TABLE EQUIPMENTBOOKING
add constraint fkey_room
foreign key (bookingdate) references roombooking (bookingdate) ;

still get the error. And still havent put in the other table one yet, its roombooking thats causing the problem. Can one help?

thanks alottry specifying the FK columns in the same order as the PK columns

in fact you should be able simply to reference the table, and it will figure out the PK

ALTER TABLE EQUIPMENTBOOKING
add constraint fkey_room
foreign key (bookingdate, sess, roomno) references roombooking|||Aaah, thanks a lot. That fixed it up. Working now, thankyou.