Chapter 10 - Program Design Flashcards
What is program design?
Program design is the act of determining what programs will be written and creating instructions for the programmers.
How are physical data flow diagrams created?
Physical data flow diagrams are made from the original Data Flow Diagrams created during analysis.
What is a structure chart used for?
A structure chart is used to depict how processes are organized and how the decisions work.
What are physical process models?
Physical process models are tools that are used to show implementation details and explain how the final system will work.
How are physical DFDs similar and different to logical DFDs?
Physical DFDs contain the same components as logical DFDs, and the same rules apply. The main difference is that a physical DFD contains extra details that describe how the system will be built.
What are the steps to make the transition from logical DFD to physical DFD?
There are five steps in converting from a logical DFD to a physical DFD:
- Add implementation references (data stores, data flows, processes)
- Draw a human-machine boundary (separate the automated from manual)
- Add system-related data stores/flows, and processes (unrelated to business).
- Update the data elements to include system-related data.
- Update metadata in the CASE (computer-aided software engineering) repository.
What is the top-down modular approach for design?
The top-down, modular approach starts with developing a high-level diagram, called a structure chart, to illustrate the organization and interaction of the parts of code with the program.
Program specifications are written to describe what needs to be included in each program module.
Once the design phase had ended, the project team creates a program design doc.
What is a structure chart?
A structure chart is a program design tool that shows all the components of code in a hierarchical format that can imply the sequence in which modules are invoked, the conditions in which they’re invoked, and how often they’re repeated.
What are the three types of processes in a structure chart?
There are three types of processes in a structure chart:
- Afferent processes, which provide inputs to the system
- Central processes, which perform critical functions in the operation
- Efferent processes, which deal with system outputs
What is a transaction structure?
A transaction structure is an arrangement of system modules that are structured around a control module, which is able to call subordinate modules, each handling a part of a particular transaction.
What is a transform structure?
A transform structure is an arrangement of system modules that are related to one another as they form a process that “transforms” some input into an output.
What are the steps taken to build a structure chart?
To build a structure chart, there are four main steps:
- Identify modules and their levels (1.0, 1.2, etc.)
- Identify special connections (loops, diamonds, etc)
- Add couples
- Revise structure charts
What is cohesion?
Cohesion is a term that refers to how well the lines of code within each module relate to one another. Good cohesion inside a module makes it easier to understand and build, because it does just one function effectively.
What are the main types of cohesion?
There are three main types of cohesion:
- Functional cohesion: All elements of the module contribute to performing a single task
- Temporal cohesion: Functions are all invoked at the same time
- Coincidental cohesion: There’s no obvious relationship between a module’s functions
What is factoring? Why is it used?
Factoring is the process of separating a function from one module into its own module. It’s used to make models more cohesive and create a better structure.
