lesson
Make permitted transitions explicit
1 · Learn
A state machine represents named states and allowed transitions. An assignment might move from draft to submitted to reviewed. A transition can require conditions, such as valid content before submission.
Drawing states is not enough: define what happens to data and permissions during each transition. Reopening a reviewed item should follow an explicit rule rather than silently erasing its history.
2 · Worked example
A submit action from an empty draft can be rejected while keeping the draft intact. A successful transition records the submission time and version.
3 · Your turn
Why should changing a reviewed submission back to draft not silently erase the reviewed version?
Check your answer
The previous version is part of the record and may be needed to understand feedback and decisions.
4 · Apply your learning
Draw a state diagram and list one permitted and one forbidden transition with reasons.
Adult guidance and safety
Use an approved sandbox, invented data and test accounts. Do not probe other systems or expose credentials. Retain test evidence and accessibility checks; these teaching models are not a completed practical project or a specified GCSE qualification.
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