Design Patterns · Middle · Question 58 of 75

How do you prevent two users from silently overwriting each other's edits of the same record?

✓Correct answer: Optimistic concurrency: send a version (or ETag) with the update and reject it if the record changed meanwhile
2Lock the record whenever anyone opens the page
3Last write always wins

Explanation

On conflict the UI can show a diff or reload the latest data. HTTP supports this with If-Match and 412 Precondition Failed.

Further reading

Martin Fowler: Unit of Work ↗

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