Backing fields that participate in seeding not work properly, when we use them for transforming (change/reformat) the data that coming from or going to the database

[ghost]

Hello,
I have a simple sample code that shows a problem with backing fields when we use them in seeding, while we use them also to transform (change/reformat) data coming from or going to the database.

This is our AppDbContext class.

public class AppDbContext : DbContext
{
    protected override void OnConfiguring(DbContextOptionsBuilder optionsBuilder)
    {
        optionsBuilder
            .UseSqlServer($@"server=.\mssqlserver20191;database={nameof(EfCoreBackingFieldSeeding)};user id=sa;password=2019");
    }

    protected override void OnModelCreating(ModelBuilder modelBuilder)
    {
        //first row - insert 
        modelBuilder.Entity<Person>().HasData(new Person { Id = 1, Name = "Kurosh", Gender = Gender.Male });
    }

    public DbSet<Person> People { get; set; }
}

And this is my Entity class.

public class Person
{
    public int Id { get; set; }
    private string _name;
    public string Name
    {
        get
        {
            return Gender switch
            {
                Male => "Mr. ",
                Female => "Miss. ",
                Other => "Dear, ",
                _ => string.Empty
            } + _name;
        }
        set => _name = value;
    }
    public Gender Gender { get; set; }

    //override
    public override string ToString() =>
        $"[Id]: {Id:00} - [Name]: {Name,-15} - [Gender]: {Enum.GetName(Gender)}";
}

We have the Gender enum type that transforms our entity Name base on the gender of the person (as you can see in the get accessor of the Name property in the above code).

public enum Gender
{
    Male,
    Female,
    Other
}

As you can see in our AppDbContext we seed our database with an instance of our Entity like this:

 //first row - insert 
 modelBuilder.Entity<Person>().HasData(new Person { Id = 1, Name = "Kurosh", Gender = Gender.Male });

After this, we add our initial migration (dotnet ef migrations add Initial). And then update our database (dotnet ef database update)

What we expected is that we have 1 row of data like this in our database(People table):

Id	Name	Gender
1	Kurosh	0

But real data in our database is this row:

Id	Name	Gender
1	Mr. Kurosh	0

•••••••

According to this code in our entity class:

private string _name;
public string Name
{
    get
    {
        return Gender switch
        {
            Male => "Mr. ",
            Female => "Miss. ",
            Other => "Dear, ",
            _ => string.Empty
        } + _name;
    }
    set => _name = value;
}

EF core didn't see _name backing field and get back his data from get accessor of Name property (add Mr. to the name of the person based on the gender)!
Where is the backing field in this scenario?

This is while when we add a new person to our database in our Program.Main method we don't have this problem (EF core see and use our _name backing field, instead of the Name property)

This is our Program class code:

class Program
{
    static AppDbContext context = new();

    static void Main(string[] args)
    {

        WriteAllPeopleInfo();
        AddThisPersonIfNotExist();
        WriteAllPeopleInfo();

        ReadLine();
    }

    static void WriteAllPeopleInfo()
    {
        List<Person> people = context.People.ToList();
        foreach (Person person in people)
            WriteLine(person);
        SeparateLine();
    }

    //second row - insert
    static void AddThisPersonIfNotExist()
    {
        if (context.People.Count() >= 2) return;

        context.Add(new Person { Name = "Dariush", Gender = Male });
        context.SaveChanges();
    }

    static void SeparateLine() => WriteLine(new string('-', 60));
}

When we run our code output is:

[Id]: 01 - [Name]: Mr. Mr. Kurosh  - [Gender]: Male
------------------------------------------------------------
[Id]: 01 - [Name]: Mr. Mr. Kurosh  - [Gender]: Male
[Id]: 02 - [Name]: Mr. Dariush     - [Gender]: Male
------------------------------------------------------------