two unfamiliar keys instead primary

i wondering, there any luck emanate list but primary key, nonetheless twin unfamiliar keys, where unfamiliar keys pairs always different?
for example, stock list item_id warehouse_id unfamiliar keys items warehouses tables. same vigilant opposite warehouses. perspective table:

item_id   warehouse_id   quantity
10        200            1000
10        201            3000
10        202            10000
11        200            7000
11        202            2000
12        203            5000

or i have emanate new primary pivotal domain automobile increment something?
the database oracle.

thanks!