Substracting values from textbox to insert in Table.

[mitchel]

Hi, I've been working on a small project and I got a problem. What I'd like is to substract a value from a text box with the value from another textbox and insert the result in the database.
E.G.
txtBox Quantity: 10
txtBox Quantity used: 4
It'd then update Quantity with "Quantity-Quantity used" and reset the Quantity used to 0. I know how to do substraction but I haven't figured out how to used the txtBox that does the substraction to insert into the Table.

Another way I thought of is filling both text box and doing the calculation when you update the selected row.



I'm currently using a macro that does something similar but it's very ineffective because it updates every field in my database which slows the whole thing.

Hope this is clear enough.

Thanks

[June7]

Why do you need to save calculated value? A principle of database design is 'enter raw data, do calcs in reports'. This is especially true with aggregate calcs.

However, if you must.

If the Quantity field is part of the form's RecordSource, can simply set the field's value in some event (form Close, button Click, textbox AfterUpdate). I don't use macros, only VBA. In the event property, select [Event Procedure], double click the ellipses (...). This will take you to the procedure in VBA editor. Type code:
Me!Quantity = Me.tbxQuantity
Me.tbxUsed = 0

[mitchel]

While I understand it'd be better to do it during a report, I still needed to do it in the form. Your code worked.

Thank you.