Software Fortresses: Modeling Enterprise Architectures

3.2. Tightly Coupled Single-Resource Transactions

I'll start with the simplest transaction variety, the tightly coupled single-resource transaction. Because all single-resource transactions are tightly coupled, I'll simplify the terminology by calling them single-resource transactions. Let me take you through a typical single-resource transaction involving a database.

Consider writing an application to withdraw money from a checking account. Let's say that “withdrawing money from a checking account” means the following:

1.	Finding the specific account record in the CheckingAccount table.
2.	Reading the CurrentBalance field.
3.	Deducting the amount from the current balance.
4.	Logging the withdrawal in a Logging table.

Imagine the problems that ...