EFCore Selects wrong column name

Question

I have created an API with .Net core and EFCore following this tutorial using the VSCode.

I have a lot of Models of my MySQL database, because i'm "migrating" my EF6 with asp.net WebAPI to .Net core, so i just have copied and paste to avoid a lot of work (again).

When i try to do a simple Get, the EFCore is concatenating two columns of diferent tables:

The Controller User

[Route("v1/[controller]")]
public class UserController : Controller
{

    private readonly IntentContext _context;

    public UserController(IntentContext context)
    {
        _context = context;
    }

    [HttpGet]
    public IEnumerable<user> GetAll()
    {
        return _context.user.ToList();
    }
}

The 'user' model

public class user
{
    public user()
    {
        user_image = new HashSet<user_image>();
        user_credit_card = new HashSet<user_credit_card>();
        user_pocket_history = new HashSet<user_pocket_history>();
        user_pocket = new HashSet<user_pocket>();

        //A lot of table instances
    }

    public string id { get; set; }
    public string username { get; set; }
    public string password { get; set; }
    public string id_account_type { get; set; }
    public int user_status { get; set; }
    public DateTime create_time { get; set; }
    public DateTime update_time { get; set; }

    public virtual account_type account_type { get; set; }

    public virtual ICollection<user_image> user_image { get; set; }
    public virtual ICollection<user_credit_card> user_credit_card { get; set; }
    public virtual ICollection<user_pocket_history> user_pocket_history { get; set; }
    public virtual ICollection<user_pocket> user_pocket { get; set; }

    //A lot of table relations
}

The table account_type

public class account_type
{
    public account_type()
    {
        this.user = new HashSet<user>();
        this.establishment_employee = new HashSet<establishment_employee>();
    }

    public string id { get; set; }
    public string account_description { get; set; }
    public string account_name { get; set; }
    public DateTime create_time { get; set; }
    public DateTime update_time { get; set; }

    public virtual ICollection<user> user { get; set; }
    public virtual ICollection<establishment_employee> establishment_employee { get; set; }
}

The terminal log during the get request

fail: Microsoft.EntityFrameworkCore.Database.Command[20102]
  Failed executing DbCommand (140ms) [Parameters=[], CommandType='Text', CommandTimeout='30']
  SELECT `u`.`id`, `u`.`Id_account_type`, `u`.`account_typeid`, `u`.`create_time`, `u`.`password`, `u`.`update_time`, `u`.`user_status`, `u`.`username`
  FROM `user` AS `u`
MySql.Data.MySqlClient.MySqlException (0x80004005): Unknown column 'u.account_typeid' in 'field list' ---> MySql.Data.MySqlClient.MySqlException (0x80004005): Unknown column **'u.account_typeid'** in 'field list'
   at System.Runtime.ExceptionServices.ExceptionDispatchInfo.Throw()

//A lot of exceptions generated 

fail: Microsoft.EntityFrameworkCore.Query[10100]
  An exception occurred in the database while iterating the results of a query for context type 'IntentAPI.Models.IntentContext'.
  MySql.Data.MySqlClient.MySqlException (0x80004005): Unknown column 'u.account_typeid' in 'field list' ---> MySql.Data.MySqlClient.MySqlException (0x80004005): Unknown column 'u.account_typeid' in 'field list'
     at System.Runtime.ExceptionServices.ExceptionDispatchInfo.Throw()

Please, note that the field u.account_typeid really doesn't exists. It is a concatenate of account_type of user table and id of account_type table.

Why it is happening?

Many thanks and sorry for my terible English

Answer 1

This is explained in the Relationships - No Foreign Key Property section of the EF Core documentation:

If no foreign key property is found, a shadow foreign key property will be introduced with the name

<navigation property name><principal key property name>

You need to specify the FK property for the user.account_type navigation property by either data annotation:

[ForeignKey("id_account_type")]
public virtual account_type account_type { get; set; }

or fluent API:

modelBuilder.Entity<user>()
    .HasOne(e => e.account_type)
    .WithMany(e => e.user)
    .HasForeignKey(e => e.id_account_type);