Table of Contents

History

Persistord.History adds append-only message history to your context. It depends on Persistord.Messages and therefore Persistord.Core.

Apply both modules in OnModelCreating — the history module requires the messages table to be present:

protected override void OnModelCreating(ModelBuilder modelBuilder)
{
    base.OnModelCreating(modelBuilder);
    modelBuilder.ApplyMessagesModule();   // required: history has a real FK to messages
    modelBuilder.ApplyHistoryModule();
}

Then expose the DbSet on your derived context:

public DbSet<MessageHistoryEntity> MessageHistory => Set<MessageHistoryEntity>();

What it records

Every change to a message is appended as a new row. Each row is a full content snapshot at that point in time — not a diff. The row is tagged with:

  • HistoryChangeType — one of Created, Edited, or Deleted.
  • RecordedAt — the timestamp when the change was recorded.

Rows are indexed on (MessageId, RecordedAt) for efficient chronological lookups.

MessageHistoryEntity shape

public class MessageHistoryEntity
{
    public long Id { get; set; }                     // surrogate PK
    public ulong MessageId { get; set; }             // FK → MessageEntity.Id
    public string? Content { get; set; }             // full snapshot at this point
    public DateTimeOffset RecordedAt { get; set; }
    public HistoryChangeType ChangeType { get; set; }
}

public enum HistoryChangeType { Created, Edited, Deleted }

Relationship to messages

MessageHistoryEntity holds a real foreign key to MessageEntity configured with DeleteBehavior.Restrict. Because messages are soft-deleted (see Soft-delete & Query Filters), the parent row is never physically removed from the database. History rows — including the row that logs the deletion — always keep a valid reference.

History requires the Messages table to be persisted. It is not a standalone audit log. You cannot use ApplyHistoryModule() without also calling ApplyMessagesModule().

See also

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