HindsightTemporal entities for EF Core on PostgreSQL

Every change to an entity kept as a version, queryable with LINQ, created by your migrations, stamped with who and why.

History lives in your migrations

Mark an entity with IsTemporal() and the next dotnet ef migrations add creates its history table and indexes. No database extensions, no superuser, no hand-written DDL.

AsOf() is plain LINQ

Ask what an entity looked like at any instant. Where, OrderBy and Select compose after it and translate into a single SQL query.

Who changed it, and why

The user, the correlation id and the reason come from your application and are stored on every version.

Catches every write

The trigger writer records ExecuteUpdate, ExecuteDelete, raw SQL and other processes, in the same transaction as the change itself.

History is never destroyed

Removing a property or a whole entity keeps its history. No migration Hindsight generates drops a history column or table.

Wrong answers throw

A query Hindsight cannot answer exactly, such as AsOf() with Include(), throws a clear exception instead of returning a plausible, wrong result.

At a glance

// Make an entity temporal; the next migration adds its history table.
modelBuilder.Entity<Policy>().IsTemporal();

// What did this policy look like when the claim happened?
var policy = await db.Policies
    .AsOf(claim.OccurredAt)
    .SingleAsync(p => p.Id == claim.PolicyId);

// Who changed it, when, and why?
var audit = await db.History<Policy>()
    .Where(v => v.Entity.Id == claim.PolicyId)
    .Select(v => new { v.ValidFrom, v.ChangedBy, v.Reason, v.Entity.Status, v.Entity.Premium })
    .ToListAsync();

Requires .NET 10, EF Core 10 with the Npgsql provider, and PostgreSQL 14 or later.