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Event Sourcing

Preview Event Sourcing Reviewed 2026-09-15 purview-dev/eventsourcing aggregates azure-cosmosdb azure-storage cqrs csharp ddd dotnet event-driven event-sourcing event-store mongodb postgresql roslyn snapshots source-generator sql-server transactions

Purview EventSourcing Wiki

Section titled “Purview EventSourcing Wiki”

This wiki is the project documentation hub for framework features, provider capabilities, and release workflow.

Start here

Section titled “Start here”

Feature highlights

Section titled “Feature highlights”
  • Core framework (Purview.EventSourcing)
    • AggregateBase, IEventStore, IQueryableEventStore, and IEventStoreTransactionFactory.
    • Transaction guarantees: atomic requirements, best-effort fallback, and failure behavior.
    • Snapshot schema versioning: compatibility detection and event-replay rebuilds.
    • Source-generated aggregate events/command wiring from partial methods.
    • Provider-agnostic aggregate load/save/query APIs.
  • Solution design
    • Paper-first worksheets for aggregate boundaries, commands, events, relationships, and event streams.
    • Guidance for relational data, value objects, validation layers, and schema evolution.
  • Storage providers
    • SQL Server / Azure SQL: append-only event streams, internal replay snapshots, and optional SQL query snapshots with transaction coordination.
    • PostgreSQL: append-only event streams, internal replay snapshots, and optional PostgreSQL JSONB query snapshots.
    • Azure Storage: table-backed event streams with blob support for snapshots/large payloads.
    • MongoDB: event streams plus an optional MongoDB query snapshot store.
    • Cosmos DB: optional query snapshot store.
    • In-memory provider: non-persistent event/snapshot store for local/test scenarios.
    • Validation adapters: FluentValidation and ZodSharp adapters for IAggregateValidator<T>.
    • SQL snapshot translation distinguishes between provider-converted scalar value objects and directly mapped complex snapshot graphs; see the provider matrix and SQL guide for details.
  • Generator behavior
    • [Aggregate] supports no base, direct AggregateBase, and transitive base-chain inheritance.
    • Property hooks are property-scoped across generated events that map that property.
    • On<Property>Changed runs in Apply(...) (including replay); On<Property>Changing runs on command/event-raise path only.
    • Event hooks (OnRaising..., OnRaised..., OnApplied...) are event-scoped.