使用实体框架生成错误的查询

Question

I need to know what am I doing wrong, because the generated query doesn't match with the attributes of the data base table and I think that my class was well type and also the mappings. Here's my code

public class Usuario
{
    #region Atributos
    private int _intID = 0;
    private Perfil _Perfil_FK = null;
    private String _strNombre = "";
    private String _strPassword = "";
    #endregion

    #region Propiedades

    public int ID
    {
        get { return _intID; }
        set { _intID = value; }
    }

    public Nullable<int> IDPerfil_FK { get; set; }

    public virtual Perfil Perfil_FK
    {
        get { return _Perfil_FK; }
        set { _Perfil_FK = value; }
    }
    public String Nombre
    {
        get { return _strNombre; }
        set { _strNombre = value; }
    }
    public String Password
    {
        get { return _strPassword; }
        set { _strPassword = value; }
    }
    #endregion
}

My test was only this _db.Usuario()

The Generated Sql query

SELECT 
[Extent1].[IDUsuario] AS [IDUsuario], 
[Extent1].[IDPerfil_FK] AS [IDPerfil_FK], 
[Extent1].[Nombre] AS [Nombre], 
[Extent1].[Password] AS [Password], 
[Extent1].[PerfilID] AS [PerfilID] <-- this attribute doesn't exit's
FROM [dbo].[Usuario] AS [Extent1];

Here's my db context class

public class MasterPageAtentoDB : DbContext
{
    public DbSet<Pagina> Pagina { get; set; }
    public DbSet<Perfil> Perfil { get; set; }
    public DbSet<Permiso> Permiso { get; set; }
    public DbSet<Usuario> Usuario { get; set; }

    protected override void OnModelCreating(System.Data.Entity.ModelConfiguration.ModelBuilder modelBuilder)
    {
        modelBuilder.Entity<Usuario>().Property(r => r.ID).HasColumnName("IDUsuario");
        modelBuilder.Entity<Pagina>().Property(r => r.ID).HasColumnName("IDPagina");
        modelBuilder.Entity<Permiso>().Property(r => r.ID).HasColumnName("IDPermiso");
        modelBuilder.Entity<Perfil>().Property(r => r.ID).HasColumnName("IDPerfil");
        modelBuilder.Conventions.Remove<PluralizingTableNameConvention>();
        base.OnModelCreating(modelBuilder);
    }
}

My database Table

Answer 1

Entity Framework doesn' recognize your property IDPerfil_FK as the foreign key property for the Perfil_FK navigation property because you are not following the naming conventions required for automatic FK property detection. As a result EF assumes that IDPerfil_FK is an ordinary scalar property and that Perfil_FK has no exposed FK property in your model and the column in the database has the standard name Perfil_ID (navigation property name + "_" + primary key property name of target entity class).

You have three options to fix this:

• Name the FK property appropriately (navigation property name + primary key property name of target entity class):

   public Nullable<int> Perfil_FKID { get; set; } 

• Put a data annotation attribute on the property to indicate that it is a FK property:

   [ForeignKey("Perfil_FK")] public Nullable<int> IDPerfil_FK { get; set; } 

• Define the FK property in Fluent API:

   modelBuilder.Entity<Usuario>() .HasOptional(u => u.Perfil_FK) .WithMany() // or with parameter if Perfil class refers back to Usuario .HasForeignKey(u => u.IDPerfil_FK); 

I would prefer the first option because your mapping of the primary key properties relies on conventions anyway, so it would be consequent to follow the conventions for the foreign key properties too.

Answer 2

I believe you can fix this as easy as adding the data annotation alerting it to your primary key.

 [Key]
 public int ID

By default EF will try to match ClassnameId as the key, if that isn't found it will try and match Id as key, otherwise it will throw an error. It is case sensitive. So if you want to use Uppercase ID you need to explicitly tag it with the [Key] annotation so it knows how to map it.

http://msdn.microsoft.com/en-us/data/gg193958 for some common annotations.