inventory system transaction form fields

[xtrareal22]

hello again,i am stuck again.Okay so i hve three tables and forms for each of those tbl
INVENTORYtble-Fields(ID,Name,quantity,price,Reorder level,Amount left)
TRANSACTIONtble-Fields(ID,TID,Quantity,Stockleft,SPrice)
ORDERtbl-Fields(ID,OID,quantity)

I added the fields"Reorder' and "Quantity" from the inventory to the transaction form.for the afterupdate event for the transaction form"Quantity"field,i created a macro to set the value of the "amount left "field by subtracting the quantity from the Inventory form with the quantity value being entered into this field.The same i have done to set the value for the "Stockleft"field.

the problem now is when i enter the ID of the item to sell, it calculates how much is left and inputs it inboth the inventory and transaction tables but when i sell the same item again it doesnt recalculate the stockleft from the amounleft but instead from the original quantity.
What do i do so when i eneter the same item it doesnt deduct it from the original quantity?

[ItsMe]

What do i do so when i eneter the same item it doesnt deduct it from the original quantity?

Have you considered not storing calculated values in your tables? You can simply "display" the calculated value at the time it matters, such as a report or in a form's unbound control.

[xtrareal22]

Okay,i will do that,