Calculating totals in access

[Which1]

In my database I have one form with a tab control on it. Each of the tabs
contain a subform. The last tab contains command buttons that open reports.
When selecting one of the reports to open information is pulled from each
subform to create the report. Most of the reports calculate totals. When
these reports calculate totals they pull information from subforms and,
divide,multiply, add or subtract with a constant I have set up in a module to
get the total to display on the report. These values, totals are not saved
in my database they are always calculated when you open the report.
My question is how can I prevent the totals from changing 5 years down the
road when I open the record and the constants may have changed?

eg:
const is percent=8
so 10 X const of 8% = 0.8

5 years down the road const is changed to percent=15
so now 10 X const of 15% =1.5

how do I retain the origional value of .08??

Thanks

 

[John Spencer]

You have to store the value in a field in a table.

You could store it with an effective date range in a separate table as long as
you have a specific date in the records you are using for your calculations.

Or you can store the percent in the records you are using for the calculation.

John Spencer
Access MVP 2002-2005, 2007-2009
The Hilltop Institute
University of Maryland Baltimore County