EFCore - Is it possible to ReloadDatabaseValues on Insert?

[pinkfloydx33]

I am aware that the ReloadDatabaseValues configuration can be used to change the behavior of modifications to entities, but I am wondering if there is a corresponding knob for doing the same on inserts?

We have a couple entities with non-key properties that are ValueGeneratedOnAdd. For example a "stored" computed column (in Postgres) or a column that is set by a database-side trigger. Unless I am missing something, there is currently no way to capture this data upon insert as the EF Core Auditing only reviews the PK/FKs after initial saving.

1. Am I overlooking some configuration?
2. Has this been considered? or,
3. Should I open a real issue for this?

---

Consider the following C# program:

Project File

<Project Sdk="Microsoft.NET.Sdk">
    <PropertyGroup>
        <OutputType>Exe</OutputType>
        <TargetFramework>net10.0</TargetFramework>
        <ImplicitUsings>enable</ImplicitUsings>
        <Nullable>enable</Nullable>
    </PropertyGroup>

    <ItemGroup>
        <PackageReference Include="Npgsql" Version="10.0.2" />
        <PackageReference Include="Npgsql.EntityFrameworkCore.PostgreSQL" Version="10.0.1" />
        <PackageReference Include="Audit.NET" Version="32.0.0" />
        <PackageReference Include="Audit.EntityFramework.Core" Version="32.0.0" />
    </ItemGroup>
</Project>

Code

using System.Text.Json;
using Audit.EntityFramework;
using Microsoft.EntityFrameworkCore;

const string pgconn = "Host=localhost;Port=5432;Database=auditfeature;Username=postgres;Password=postgres";

Audit.Core.Configuration.Setup().UseInMemoryProvider(out var provider);
Audit.Core.Configuration.ExcludeEnvironmentInfo = true;

Configuration.Setup()
    .ForAnyContext(c => c.ExcludeValidationResults().IncludeEntityObjects(false).ReloadDatabaseValues())
    .UseOptOut();

var opts = new DbContextOptionsBuilder<TestContext>()
    .UseNpgsql(pgconn, s => s.SetPostgresVersion(new Version(17, 0)))
    .Options;

await using (var ctx = new TestContext(opts))
{
    await ctx.Database.EnsureDeletedAsync();
    await ctx.Database.EnsureCreatedAsync();

    var thing = new Thing { Name = "My Thing" };
    ctx.Things.Add(thing);
    await ctx.SaveChangesAsync();
    
    Console.WriteLine("Thing #{0} Written with InitialNameLength=={1}", thing.Id, thing.InitialNameLength);
    
    thing.Name = "New Name";
    await ctx.SaveChangesAsync();
}

foreach (var p in provider.GetAllEvents())
{
    var ef = p.GetEntityFrameworkEvent();
    Console.WriteLine(JsonSerializer.Serialize(ef));
    Console.WriteLine("-----");
}

public sealed class TestContext(DbContextOptions<TestContext> opts) : AuditDbContext(opts)
{
    public DbSet<Thing> Things => Set<Thing>();
    
    protected override void OnModelCreating(ModelBuilder modelBuilder)
    {
        modelBuilder.Entity<Thing>(e =>
        {
            e.ToTable("things");
            
            e.HasKey(p => p.Id);
            e.Property(p => p.Id)
                .ValueGeneratedOnAdd()
                .HasDefaultValueSql("gen_random_uuid()")
                .HasColumnName("id");

            e.Property(p => p.Name)
                .IsRequired()
                .HasColumnName("name");

            e.Property(p => p.InitialNameLength)
                .IsRequired()
                .HasComputedColumnSql("LENGTH(name)", true)
                .HasColumnName("initial_name_length")
                .ValueGeneratedOnAdd();
        });
    }
}

public sealed class Thing
{
    public Guid Id { get; set; }
    public string Name { get; set; } = null!;
    public int InitialNameLength { get; set; }
}

The database has a "stored" computed column (only computed on insert, never updated) with an initial value of 8 (equivalent to "MyThing".Length). After SaveChangesAsync is called, EF has already re-queried the value back from the database which the console logged message immediately after shows:

Thing #c270d934-b85e-4176-94fe-c39932c30191 Written with InitialNameLength==8

However the audit doesn't capture it that way and instead reports inital_name_length as having a value of 0.

  "Entries": [
    {
      "Table": "things",
      "Name": "Thing",
      "PrimaryKey": {
        "id": "c270d934-b85e-4176-94fe-c39932c30191"
      },
      "Action": "Insert",
      "ColumnValues": {
        "id": "c270d934-b85e-4176-94fe-c39932c30191",
        "initial_name_length": 0,
        "name": "My Thing"
      }
    }
  ]

But the audit recorded by the subsequent/immediate update shows the field as starting with the appropriate value!

  "Entries": [
    {
      "Table": "things",
      "Name": "Thing",
      "PrimaryKey": {
        "id": "c270d934-b85e-4176-94fe-c39932c30191"
      },
      "Action": "Update",
      "Changes": [
        {
          "ColumnName": "name",
          "OriginalValue": "My Thing",
          "NewValue": "New Name"
        }
      ],
      "ColumnValues": {
        "id": "c270d934-b85e-4176-94fe-c39932c30191",
        "initial_name_length": 8,
        "name": "New Name"
      }
    }
  ]

[thepirat000]

The current behavior of ReloadDatabaseValues is to determine whether the original values of audited entities should be retrieved from the database before any update or delete operation. It does not apply to inserts, as there are no original values in that case.

I will evaluate adding a separate setting to reload values after the SaveChanges operation, to support scenarios involving computed columns that are generated by the database.

[thepirat000]

Please check #787