Hi all, i am having this issues.

I want to make a function, that will loop until column "a" of a record have a new update.
Example:

i have a product record with quantity is 3 . I want to make a function to do a loop until quantity of product is updated.

How can i do it ? Actually i was make a test like this:

while product.qty == 3:

   continue

and i update qty of product become 5 by SQL query in third party, but in the loop, it always show qty is 3.
Have anyway to do it ? 
I need your help so much.
Thank you