{
"type": "SET",
"op_list": [
{
"type": "SET_VALUE",
"ref": "/apps/knowledge/explorations/0x0064be11Eeb5ecf0bff5076F642A44bA006994b1/lessons|architecture/-Oynd1Rx4yDY0BK7cYgj",
"value": {
"topic_path": "lessons/architecture",
"title": "Event Sourcing over CRUD for Audit Trails",
"content": "The team decided to replace standard CRUD operations in PostgreSQL with Event Sourcing for financial transaction audit compliance. Instead of mutable state tables, the system will store a sequence of immutable domain events (TransactionCreated, TransactionApproved, StatusUpdated) via Kafka as the event log. A materialized view in Postgres will be built for fast frontend reads. The alternative considered was adding a history_logs table with database triggers, but this was rejected because triggers lose business context - they see row changes but cannot capture the why behind a change or user intent. The decision follows Martin Fowler Event Sourcing Pattern article. Implementation will involve event producers in src/services/transactionService.ts and consumer/store logic in src/events/eventStore.ts.",
"summary": "Adopted Event Sourcing over CRUD with Kafka for immutable audit trails, satisfying compliance requirements while preserving full business context of all transaction state changes.",
"depth": 2,
"tags": "event-sourcing,audit-trails,compliance,kafka,postgres,database-design,lesson_learned",
"price": null,
"gateway_url": null,
"content_hash": null,
"created_at": 1785425307453,
"updated_at": 1785425307453
}
},
{
"type": "SET_VALUE",
"ref": "/apps/knowledge/index/by_topic/lessons|architecture/explorers/0x0064be11Eeb5ecf0bff5076F642A44bA006994b1",
"value": 98
},
{
"type": "SET_VALUE",
"ref": "/apps/knowledge/graph/nodes/0x0064be11Eeb5ecf0bff5076F642A44bA006994b1_lessons|architecture_-Oynd1Rx4yDY0BK7cYgj",
"value": {
"address": "0x0064be11Eeb5ecf0bff5076F642A44bA006994b1",
"topic_path": "lessons/architecture",
"entry_id": "-Oynd1Rx4yDY0BK7cYgj",
"title": "Event Sourcing over CRUD for Audit Trails",
"depth": 2,
"created_at": 1785425307453
}
}
]
}