Transaction Details

Transaction Hash
0x4cc062f7cad2327c10d69b398d8fa238f13cbbd6903251387a6611ad796282e5
Timestamp
Sep 4, 2026, 06:02:43 PM
Nonce
698
Operation Type
SET

Operation

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        "topic_path": "lessons/architecture",
        "title": "Event Sourcing over CRUD for Financial Transaction Audit Trails",
        "content": "The team decided to move from standard CRUD operations in PostgreSQL to the Event Sourcing pattern for financial transaction audit trails. The current CRUD approach overwrites previous states, making it impossible to provide compliance history (e.g., who changed transaction #8821 status from pending to approved). Database triggers with a history_logs table were considered and rejected because triggers lose business context — they only see row-level changes without knowing WHY the change happened or the user intent. The chosen architecture uses Kafka to store an immutable event log of domain events (TransactionCreated, TransactionApproved, StatusUpdated, etc.) and builds a materialized view in PostgreSQL for fast frontend reads. This follows Martin Fowler's 'Event Sourcing Pattern' article. Implementation by Bob: event producers in src/services/transactionService.ts, consumer/store logic in src/events/eventStore.ts.",
        "summary": "Move from standard CRUD to Event Sourcing with Kafka for financial transaction audit trails, ensuring compliance history with full business context. References Martin Fowler's Event Sourcing Pattern.",
        "depth": 2,
        "tags": "lesson_learned,event-sourcing,audit-trail,compliance,postgresql,kafka,financial-transactions,CRUD",
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