Ask HN: How to Create Data Flow Diagrams?

I can make context diagram, but how to make level 1 and level 2 DFD? Unless I've idea about how software is going to work, making this isn't possible. But in exam it asks me to write a dfd for online examination system lol.

4 points | by shivajikobardan 2 days ago

1 comments

  • rajeshpatel15 2 days ago
    Start with Common System Functions For any system (like online examination), think in terms of core business processes:

    Level 1 DFD - Break down your context diagram into major processes:

    User Management (login, registration, authentication)

    Content Management (questions, exams, results)

    Examination Process (take exam, submit answers)

    Reporting/Analytics (generate reports, view results)

    Level 2 DFD - Decompose Each Process Take one Level 1 process and break it further:

    Example: "Examination Process" becomes:

    Validate student eligibility

    Display questions

    Capture answers

    Calculate scores

    Store results

    Practical Exam Strategy When stuck, use this template:

    Input processes (what comes into the system)

    Processing/Business logic (what the system does)

    Output processes (what goes out)

    Storage interactions (read/write to data stores)

    Quick DFD Rules Each process needs inputs and outputs

    Data flows between processes, not between external entities

    Every data store should be accessed by at least one process

    Number processes: 1.0, 2.0, 3.0 (Level 1), then 1.1, 1.2, 1.3 (Level 2)