- Context diagrams Yourdon/DeMarco. 11ATAR, 12 GEN, 12 ATAR
- Data flow diagrams (DFD) Yourdon/DeMarco 11 ATAR, 12 ATAR
- System manuals 12 ATAR
- User manuals 12 ATAR
- Documentation is essential for any information system and / or product
- Some documentation helps developers and designers to understand the ins and outs of the system or project, as well as a an integral part of planning
- Other documentation is created specifically to help the end-user operate the system
Context Diagrams (Yourdon/DeMarco)
- A system context diagram, or context diagram, is a diagram used to show the high-level processes of a system
- These processes are shown along with how they interact with external entities
- Data is shown as to be "flowing" between the system and external entities, as depicted with arrows
- Context diagrams are a step before Level-0 DFDs (data flow diagrams) and use similar symbols
- A process is represented with a circle
- An external entity is represented with a rectangle
- A data store is represented with two parallel lines
- A data flow is represented with a straight line and arrow head in the direction of the flow
- Context diagrams only show essential general processes without breaking down each step
Data Flow Diagrams (Yourdon/DeMarco)
- A data flow diagram is also known as a DFD
- It's the next level up from a context diagram, where we look at each process and break it up further in easy-to-read data flows
- These data flows are how the system interacts with external entities, as well as databases
- The processes are numbered with decimals, meaning the first process will have sub-processes in a DFD numbered as "1.1", "1.2" etc.
- Data flow diagrams use the same symbols as a context diagram
- Refer to the section "For you to do" below, number 2, for more on DFDs.
System Manuals (12 ATAR only)
- System manuals can also be referred to as internal documentation
- Internal documentation refers to notes and instructions within projects, often seen only by developers
- This includes comments within the source codes of a project
- System manuals are generally created for developers and people within the project
User Manuals (12 ATAR only)
- User manuals can also be referred to as external documentation
- External documentation is any form of manual or guide used to instruct the end-user of a system
- User manuals are generally created for end-users in order to educate them on how to use the system
- Create online diagrams here OR just do sketches by hand.
- Learn how to create context diagrams and data flow diagrams here
- Learn about Data Flow Diagrams from this Wiki 'Structured Analysis'
For you to do!
1. What does DFD stand for? What is the purpose of a DFD?
2. How is a process represented? Does it start with a verb or noun?
3. How is an external entity represented? Does it start with a verb or noun?
4. What is an entity?
5. How is a data store represented? What is it?
6. What is a context diagram?
7. What does a data flow look like?
Found an error or have an enhancement? Please let us know via this contact form