Current valued data are data that are accurate as of the moment of access. In order to
achieve this high degree of accuracy, the application must support online transaction
processing.

As a simple example of current value data, consider the account balance for a husband
and a wife. At 8:00 a.m., their account balance has $5000. At 9:15 a.m., the wife does an
ATM withdrawal of $500. At 9:15 a.m. and 5 seconds, the account balance is corrected
to $4500.

The husband checks the account balance at 10:00 a.m. and sees that the account balance
is $4500. The husband withdraws $175 as of 10:01 a.m. At 10:01 a.m. and 5 seconds, the
account now has $4325.

At 4:15 p.m., the wife deposits a check into the account for $2000. As of 4:15 p.m. and 5
seconds, the account balance is now $6325.

At any point in the day, the husband, the wife, and the bank can check the account
balance and see what the balance in the account is. The account balance is accurate as of
the moment of access to the data.

Current value data are data that are accurate as of the moment of access. Applications
that interact directly with the customer are typically populated with current value data.

The converse of current value data is data that are not accurate as of the moment of
access. As a simple example of noncurrent value data, consider the stock market where
values are captured at the end of the trading day. Suppose there is an application that
captures data as of the end of a trading day.

At 9:00 a.m., you look at your favorite stock. You found that its closing value the day
before was $76.10. However, the market has been open for several hours now. The stock
may well be trading higher or lower than $76.10. But your stock value won’t be updated
until the end of the trading day.

Minimal Historical Data

Another characteristic of the data found in siloed applications is that there is relatively
little historical data found in the application. If there is any amount of historical
information found in the application, it is summarized.

Chapter 5.1: The Siloed Application Environment