Start by clarifying requirements and constraints, then propose a data model that separates the current recipe state from an append-only version history. Outline the API changes for create/edit to atomically append version records, and describe how to efficiently retrieve the ordered version list. Discuss trade-offs and potential optimizations.
Pro tip: Emphasize atomicity and immutability: version records should be append-only and written in the same transaction as the recipe update to avoid inconsistencies. Also mention that storing a snapshot of the full recipe in each version simplifies retrieval and auditing, even if it uses more storage.
Ask about expected read/write patterns, version retention, and whether versions need to store full snapshots or deltas. Confirm if ordering is by timestamp or a monotonic version number.
Propose a Recipe table for current state and a RecipeVersion table with recipe_id, version_number, timestamp, and snapshot (or delta). Ensure version_number is sequential per recipe.
Wrap recipe creation/update and version insertion in a transaction. On create, insert recipe and first version; on edit, update recipe and append new version with incremented version_number.
Provide a function that queries RecipeVersion by recipe_id, ordered by version_number ascending. Consider pagination for large histories.
Address storage overhead of snapshots vs. deltas, indexing for performance, and potential features like version diffing or rollback.
AI-generated suggestions, not part of the candidate's original notes. May be inaccurate — verify before relying on them.
Start by clarifying the data model and versioning semantics, then outline a transactional algorithm that validates the target version, computes the restored state, and atomically appends a new version with author 'rollback'. Emphasize failure handling: check preconditions, use optimistic concurrency or locking, and ensure no partial writes on conflict.
Pro tip: Mention that the rollback itself should be versioned and immutable, so the history remains append-only and auditable—this mirrors real-world event sourcing and avoids destructive updates.
Ask about the version storage format (e.g., full snapshots vs. deltas), how versions are identified, and what constitutes a conflict (e.g., concurrent writes). Confirm that rollback creates a new version rather than deleting history.
Outline steps: fetch the target version, validate it exists and is accessible, compute the restored recipe state, and prepare a new version entry with author 'rollback'. Use a transaction or compare-and-swap to ensure atomicity.
Enumerate failures: target version not found, permission denied, concurrent modification (optimistic lock failure), storage errors. For each, specify the error returned and confirm no state mutation occurs.
Compare full snapshot vs. delta rollback, optimistic vs. pessimistic locking, and synchronous vs. asynchronous rollback. Explain why you chose your approach based on consistency, performance, and complexity.
Walk through a sample scenario: recipe with versions v1, v2, v3; rollback to v1 creates v4 with author 'rollback'. Show how a conflict (e.g., v3 modified concurrently) is detected and handled without side effects.
AI-generated suggestions, not part of the candidate's original notes. May be inaccurate — verify before relying on them.