How to subtract Monthly Installment based on date?

[ghost]

Greeting,

I have car show porgramm for traking the monthly installment for each car. I
have the following fields:

CarNO
Type
Monthly installment
Installment Date
Value
Reminder value

What I need is calculating the reminder value once I input the date and
installment value but in the beginning of each month. How can I do that
without saving any details??

Thanks!!

 

[Arvin Meyer [MVP]]

Storing calculations in a relational database is a violation of
Normalization rules. Since it is quite easy to recalculate with a query,
you'll never need to store it anyway.

What you need to store is:

CarNo - PK
Type
PurchaseDate
InstallmentDate (only if not the same as the purchase date)
InstallmentAmt
Value (or really cost, since the value changes)

You can then count the number of whole months since the purchase date and
multiply by the InstallmentAmt, then subtract from the Cost.