Hi,
I am doing Stock Adjustment module in POS system. In My module, I need to SUM out the total of goods purchased, goods returned to rupplier, totals goods sold, total good return by curstomer and so on in order to calculate the sotck run out and adjust thwe stock with the physical stock key in by user.
I have a problem to make sure the data accuracy. Since I need to calculate the item as mentioned as above, it may take some time (may be 2 seconds or more for each ) because it may contains many records.
How should I gurantee the total calculated for each of them are accurate since there may be some changes during the calculation time for each table?

Thank you