3 tables are mainly used to manage the stock :
cataloginventory_stock
, cataloginventory_stock_item
and cataloginventory_stock_status
If you need to update a product's stock quantity you will need to find the relevant line in the cataloginventory_stock_item
table and edit the qty field:
Example (set qty to 100 for product ID 33) :
UPDATE cataloginventory_stock_item set qty=100 where product_id=33