EF5-> EF6奇怪的迁移行为

Question

We have an ASP.Net MVC4 project that has been using Entity Framework 5 for a year now. We just updated to Entity Framework 6 using the NuGet Package Manager and now we are getting odd behavior in the migration generation.

A Many-to-many table that existed correctly, now EF wants to add an additional column and FK... and Columns that have the [NotMapped] attribute are NOT being ignored. I had to use .Ignore()

Here is the relevent code for the Many-to-many that has been working with EF5, but suddenly doesn't want to work with EF6...

public class Grade
{
    [Key]
    public int GradeKey { get; set; }
    [Required]
    public string GradeLevel { get; set; }

    public virtual ICollection<Test> Tests { get; set; }
}

public class Test
{
    [Key]
    [HiddenInput(DisplayValue = false)]
    public int TestKey { get; set; }

    ...

    [UIHint("_GradeCheckboxes")]
    [Order(5)]
    [Display(Order = 5)]
    [DisplayName("Grades")]
    public virtual ICollection<Grade> Grades { get; set; }
}

//Fluent API for the join
modelBuilder.Entity<Grade>().HasKey(p => p.GradeKey).HasMany(p => p.Tests).WithMany(d => d.Grades).Map(x => 
{
    x.MapLeftKey("Grade_GradeKey"); 
    x.MapRightKey("Test_TestKey");
    x.ToTable("GradeTests");
});

// Migration
public override void Up()
{
    AddColumn("dbo.Grades", "Test_TestKey", c => c.Int()); // This is a problem
    AlterColumn("dbo.Students", "StateCode", c => c.String()); // This already exists in DB
    AlterColumn("dbo.Students", "SchoolName", c => c.String()); // This already exists in DB
    CreateIndex("dbo.Grades", "Test_TestKey"); // Problem
    CreateIndex("dbo.StudentTests", "StudentKey");
    CreateIndex("dbo.StudentTests", "TestKey"); 
    AddForeignKey("dbo.Grades", "Test_TestKey", "dbo.Tests", "TestKey"); // Problem
    AddForeignKey("dbo.StudentTests", "StudentKey", "dbo.Students", "StudentKey", cascadeDelete: true); // Already exists
    AddForeignKey("dbo.StudentTests", "TestKey", "dbo.Tests", "TestKey", cascadeDelete: true); // Already exists
}

Has anyone else experience this problem when upgrading or with EF6 in general. I have tried many different tactics and internet searches to try and solve this issue for a few days now. I have even removed the __MigrationHistory table and deleted all of the migrations and has it start fresh from the models alone, but it still wants to create the Test_TestKey column in the Grades table instead of in the Many-to-many table...

Answer 1

I have dropped the [Key] attribute from Grade and tested and works as expected when intialising a basic database

public class Grade
{

    public int GradeKey { get; set; }
    [Required]
    public string GradeLevel { get; set; }

    public virtual ICollection<Test> Tests { get; set; }
}

fluent api is the same asyours when building many to many table

 modelBuilder.Entity<Grade>()
                    .HasKey(g => g.GradeKey)
                    .HasMany(g => g.Tests)
                    .WithMany(t => t.Grades)
                    .Map(map =>
                        {
                            map.ToTable("GradeTests");
                            map.MapLeftKey("GradeKey");
                            map.MapRightKey("TestKey");
                        });

Database tables