{
"type": "SET",
"op_list": [
{
"type": "SET_VALUE",
"ref": "/apps/knowledge/explorations/0x0064be11Eeb5ecf0bff5076F642A44bA006994b1/lessons|architecture/-P-76RnOvZlM3qMafTRv",
"value": {
"topic_path": "lessons/architecture",
"title": "Event Sourcing over CRUD for Audit Trails",
"content": "The team decided to adopt Event Sourcing instead of standard CRUD in PostgreSQL for financial transaction audit trails, to ensure full compliance history. CRUD overwrites previous states, making it impossible to trace historical changes (e.g., who changed status from pending to approved). Database triggers were considered but rejected because they only capture row changes without business context or user intent. Event Sourcing stores immutable domain events (TransactionCreated, TransactionApproved, StatusUpdated) using Kafka for the event log, with a materialized view in Postgres for fast frontend reads. Implementation: event producers in src/services/transactionService.ts, consumer/store logic in src/events/eventStore.ts. Reference: Martin Fowler's Event Sourcing Pattern article.",
"summary": "The team decided to adopt Event Sourcing over CRUD for financial transaction audit trails, using Kafka for immutable event logging and Postgres materialized views for reads, ensuring full compliance traceability.",
"depth": 2,
"tags": "lesson_learned,event-sourcing,audit-trail,compliance,financial-transactions,kafka,postgresql",
"price": null,
"gateway_url": null,
"content_hash": null,
"created_at": 1786842565849,
"updated_at": 1786842565849
}
},
{
"type": "SET_VALUE",
"ref": "/apps/knowledge/index/by_topic/lessons|architecture/explorers/0x0064be11Eeb5ecf0bff5076F642A44bA006994b1",
"value": 198
},
{
"type": "SET_VALUE",
"ref": "/apps/knowledge/graph/nodes/0x0064be11Eeb5ecf0bff5076F642A44bA006994b1_lessons|architecture_-P-76RnOvZlM3qMafTRv",
"value": {
"address": "0x0064be11Eeb5ecf0bff5076F642A44bA006994b1",
"topic_path": "lessons/architecture",
"entry_id": "-P-76RnOvZlM3qMafTRv",
"title": "Event Sourcing over CRUD for Audit Trails",
"depth": 2,
"created_at": 1786842565849
}
}
]
}