ORM.cs

class Error<T>
{
    public Func<T> Unfetched = () => { throw new Exception("Unfetched"); };
}

static class Errors
{
    public static Error<string> String = new Error<string>();
    public static Error<float> Float = new Error<float>();
}

class Person  {
    public Func<string> Name = Errors.String.Unfetched;
    public Func<float> Age = Errors.Float.Unfetched;
    public Func<int, bool> FetchById;

    public Person()
    {
        FetchById = (int id) =>
        {
            if (new Random().Next(0, 50) == 0)
            {
                Name = Errors.String.Unfetched;
                Age = Errors.Float.Unfetched;

                return false;
            }

            var dataRow = new { Age = 20, Name = "Joe Blow" };

            Name = () => dataRow.Name;
            Age = () => dataRow.Age;

            return true;
        };
    }
}