Current stock calculation

i want current stock of the product in my app
current stock(V C) created
there are 2 tables

  1. stock in

ID
product(ref)
date
quantity
remarks
store point(enum)

2nd Table stock out contains

STOCK OUTID
PRODUCT NAME(ref)
DATE
QUANTITY
REMARKS
STORE PONT(enum)

I have to display the current stock of a product by strore point.

if stock out a product from a particular store point, the current stock of that product has been decreased only in that store point

how is this possible??

if anyone who knows about this please help???