Unit 3: Software development
Area of Study 2: Software development: analysis and design
Outcome 2
Analyse and document a need or opportunity, justify the use of an appropriate development model, formulate a project plan, generate alternative design ideas and represent the preferred solution design for creating a software solution.
Examples of learning activities
Detailed example
Analytical tools
The VCE Applied Computing Study Design lists context, data flow and use case diagrams as the analytical tools that students must use when analysing existing processes and information systems. Each of these analytical tools contains distinct features (symbols and conventions) that students must understand the meaning of, and they must also know how to apply them within different scenarios. As part of the teaching of the use of these tools, students should be given time to analyse a number of case studies and produce analytical tools representative of the case study.
Teachers can prepare case studies around context-relevant scenarios that are accessible to students and provide students with opportunities to interpret, deconstruct and synthesise the information in front of them. Scenarios that teachers may consider using include:
- food or product ordering systems
- online services
- banking services
- school learning management systems/school intranets.
Teachers can provide students with incomplete representations of the information system described in the case studies, with students required to complete the diagram by drawing symbols or filling in the gaps. This approach also helps students to develop confidence in their abilities.
Once students have developed their abilities in working with the tools, they should be given opportunities to create entire diagrams from scratch. Teachers should provide students with a framework to develop context, data flow and use case diagrams. Below are examples of approaches that teachers may suggest to their students.
Context and data flow diagrams
- Identify or highlight information within the case studies that describes entities and the system.
- Construct a context diagram by drawing the system at the centre of the page, with the entities sitting outside of the system, linked by the incoming and outgoing data flows.
- Identify or highlight information within the case studies that describes the processes within the system, the data flows and data stores.
- On another page, draw the entities around the outer edge of the page.
- Start the construction of the data flow diagram by drawing each of the processes (circles).
- Draw the data stores in an appropriate part of the page.
- Link the entities, processes and data stores using data flows as required, ensuring that outgoing data flows are different to the data flows entering a process and flow direction is depicted.
Use case diagrams
- Identify or highlight information within the case studies that describe system roles and actions.
- In a vertical manner, draw each of the system actions as use cases (ellipse).
- Where actions are part of other actions, depict <<includes>> or <<extends>> relationships using the correct arrows (dashed and relevant direction). (The use of incorrect arrow directions is a common mistake made by students in examinations.)
- Draw a box around the set of use cases to represent the system boundaries.
- Around the box of use cases, draw each of the system roles as actors (stick figures).
- Connect the use cases and relevant actors using solid lines. Where an actor initiates a use case, the interaction should have an arrow pointing to the use case.