Continued previous problems 1. Originally, I should continue in the last article, but I found that I can't edit the preserved article, only one another.
Now say the topic. Why is the processing between the DFDs in DFDs often do not continuous?
Not continuous, that is, between the various processing in the DFD is often more independent, there is no data flow between each other, and the entire DFD is like an island that is isolated from each other. Saying "not directly connected" is also not completely unsatisfactory, such as a processed "historical" data generated by another processing. However, as appropriate in the examples of the book, it can be seen that in the example in the book (such as page 237), there is generally a data stream between each process, which can be obvious. The time in each processing process is time. And my ticket sales DFD is not as shown in the figure.
For example, there is no data stream between 2.1, 2.2, 2.3, 2.4.
Processing between each other is connected by data streams, depending on the characteristics of the change in shift or the event, it can be converted to a module between the call relationships between each other. There is also a detailed introduction in the rules of the conversion (Chapter 13, 14). But if there is no association between the machining, what should be transformed into a design, what should be like a transformation? Or should not have a process that is isolated from each other, which is a wrong analysis?
Question 2: Does the processing in the DFD do not significantly expand the processing under processing and failure of failure? Still implicit in processing?
For example, there is such a function to do:
The machining A is executed, and the data DATAA is generated. If the machining A is successfully executed, the machining B is performed, otherwise the machining A1 is performed.
Processing B uses DataA as input. If the machining B is successfully executed, the machining C is performed, otherwise the processing B1 is performed.
Processing C requires user input and storage data Datac for processing. If the machining C is executed, the machining C1 is performed, otherwise the processing C2 is performed.
Processes A1, B1, C1, and C2 are divided into two sections: display some information, perform some operations and return.
According to the question 2, two divisions are carried out, as shown in the following two figures. The first figure is the success or failure of the displayed manifestation, and the other map does not significantly indicate that the machining is successful or failed, and the success or failure of processing is contained in the processing itself.
Thinking: Which type of processing is more reasonable?
