3 way tables or code to fix my mistake

Hi All,

I have 3 tables. Category(typeid), item (itemid) & deployed items (lockeritemid)- which are using itemid then lookup to get the full item name.
I forgot to copy over the category ids to deployed items, where i need it. the items tables, have the typeid assigned.

Can i make a button/code to correct this mistake such as: where deployed forall itemid = itemid in item table, copy typeid to deployed items table typeid field?

or can you do a 3 table lookup, itemid = itemid, then that itemid whats the typeid on that record ?