General :: Maintain Stock From Daily Input-output Table

i have a production database in which i have different sections processing on the same product. i have a daily production entry form on which datewise entry is done for each section.

i want to maintain the total stock of each section (sectionB) with productName, input from sectionA , production from sectionB, balance (input-production) . presently i used query for this .. but i need a stock table in which entries should be inserted by an automatic query .. how should i achieve this :

1. by an append query who runs every time to append the quantity when a daily entry is made .??
2. by an update query to replace the quantity with a qty from totals query ?

i.e. what is the best method to maintain inventory from input & output tables ?