Soft Delete

public interface ISoftDeletable
{
    DateTime? DeletedAt { get; }
    Guid?     DeletedBy { get; }
    bool IsDeleted();          // DeletedAt.HasValue
}

case EntityState.Deleted:
    entry.State = EntityState.Modified;              // DELETE → UPDATE
    entry.Property(nameof(ISoftDeletable.DeletedAt)).CurrentValue = now;
    entry.Property(nameof(ISoftDeletable.DeletedBy)).CurrentValue = userId;
    break;

foreach (var entityType in modelBuilder.Model.GetEntityTypes())
{
    if (!typeof(ISoftDeletable).IsAssignableFrom(entityType.ClrType))
        continue;

    var param  = Expression.Parameter(entityType.ClrType, "e");
    var prop   = Expression.Property(param, nameof(ISoftDeletable.DeletedAt));
    var body   = Expression.Equal(prop, Expression.Constant(null, typeof(DateTime?)));
    var lambda = Expression.Lambda(body, param);

    modelBuilder.Entity(entityType.ClrType).HasQueryFilter(lambda);
}

var allIncludingDeleted = await db.Faqs
    .IgnoreQueryFilters()
    .ToListAsync(ct);

/// <summary>
/// Soft-delete edilmiş kaydı geri alır.
/// Aynı (RoleId, PermissionId) çifti yeniden atanmak istendiğinde
/// yeni INSERT yerine bu method çağrılır (duplicate PK'den kaçınmak için).
/// </summary>
public void Restore()
{
    DeletedAt = null;
    DeletedBy = null;
}

builder.HasIndex(rp => new { rp.RoleId, rp.PermissionId })
    .IsUnique()
    .HasFilter("deleted_at IS NULL")
    .HasDatabaseName("ix_role_permission_role_id_permission_id_active");