The shop staff repeat the same changes every day. Save them as procedures.

1. Create a procedure add_stock(p_id integer, qty integer). It adds qty to the stock of product p_id.
2. Try SELECT add_stock(3, 25);. Which keyword does the HINT tell you to use?
3. Run your procedure: the Daemon Cat Plush (product 3) gets 25 new units.
4. Create a procedure place_order(o_id integer, c_id integer, p_id integer, qty integer). It makes three changes:
   • adds order o_id for customer c_id, with today's date and status pending,
   • adds the item: product p_id, quantity qty, unit price = the product's current price,
   • takes qty off the product's stock.
5. Run it: Yuki Tanaka (customer 9) orders 3 Linux Sticker Packs (product 7) as order 116.