hi..
i have a problem about my database form...
my database actually to input report from every branches about their
sales or stock....
my problem is how to make one field in the form appear automatically...
that field represent opening stock for every product...
so i want to control stock by use amout of closing stock in previous day
to become opening stock on next day....

Your stock level is calculated basically using other stock records suchas:

InStock = TotalStockIn - TotalStockOut

Correct?

TotalStockIn and TotalStockOut are functions of other records that you have like:

TotalStockIn = Sum of all records you have about stock supplied to company

TotalStockOut = Sum of all records you have about stock supplied by the company

It is very bad practice to calculate stock level figures and record them in tables as these figures can be calculated at run-time from other records.

The above can be done using sum queries based on your stock supplies and stock out tables.

Ian