Re: Mapping SQL Result Sets to Browsers

[Nathan Andelin <nandelin@xxxxxxxxx>]

> From: Joe Pluta
> this sort of (programmer) performance gain very easily translates 
> into performance LOSS for the user.  In the above situation, let's
> take the calculation.  Is it performed when the Item object is loaded?
> Or when the property is requested?

I've been considering that question.  Particularly as it relates to "available balance" in bank accounts, which is a calculated value.  And the algorithm can be quite complex.  Holds of various amounts may be in effect, and may have various durations, and come from various sources (questionable deposits from questionable sources, loan collateral, minimum balance requirements, scheduled withdrawals, etc.).

> In the former case it will be calculated and often never used, while
> in the latter case it will be calculated over and over again.

And back to the banking application "available balance" may be calculated one way when the customer is viewing the account over the Internet or standing in front of the teller window, but calculated another way when a batch process is clearing checks or automated loan payments or ACH transactions, or automated transfers, or  ATM transactions, or debit card transactions from merchants, where overdraft protection may or may not come into play.

Available balance may calculated differently based on type of account (Checking, Savings, IRA, SEP, Certificates of Deposit, Credit Card, etc.)

I guess the point, is that you may need to plan for a lot of flexibility, and change as business rules change.

Nathan.