Transaction Mapping

In various software applications a single data item triggers one or a number of information flows which effect a function implied through the triggering data item.  Data item is called a transaction and its corresponding flow characteristics were discussed in past section we consider design steps used to treat transaction flow.

An example

Transaction mapping will be described through considering the user interaction subsystem of the Safe Home software. Stage 1 data flow for this subsystem is described as part of figure . By Refining the flow a stage 2 data flow diagram a corresponding CSPEC, data dictionary and   PSPECs would also be created is established and described in figure .

As demonstrate in figure a user commands flows into the system and results in additional information flow behind one of three action paths.  The single data item, command type causes the data flow to fan outward from a hub. Thus, the overall data flow characteristic is transaction-oriented.

It should be noted in which information flow behind two of the three action paths accommodates additional incoming flow example for system parameters and data are input on the configure action path.  Each and every action path flows into a single transform that display status and messages.