Here is an article which provides an introduction to Context Diagrams. It also includes examples of Context Diagrams:
Introduction to Context Diagrams
Here are a couple of more resources related to context diagrams as they might appear in an interview:
What is a Context Diagram and what are the benefits of creating one?
The Context Diagram shows the system under consideration as a single high-level process and then shows the relationship that the system has with other external entities (systems, organizational groups, external data stores, etc.)...
What approach should be taken when creating a Context Diagram? Top down? Bottom up?
A number of factors should be considered when deciding what approach to use (top down or bottom up) to create a Context Diagram. First let’s be clear about what each approach means...
Adrian:
I especially enjoyed the "Top Down? Bottom Up?" article!! Many espouse only a top down approach of drawing a Context Diagram, and then drawing lower level Use Cases. However, as the ariticle states, for larger scale efforts, a top down approach is often too hard. And trying to summarize Use Cases upwards into a Context Diagram is mixing apples and oranges. The person who wrote the article demonstrates "street smarts" that is lacking in too many books and college courses.
Tony
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