Many to many table insert problem in MVC-Code First

Question

Yesterday I asked a question and later I say solved the problem. But today the same error occurred again.

I have three tables `dbo.Food`, `dbo.Menu` and `dbo.FoodMenu` which is the many-to-many link table - like this:

* dbo.Food { ID, FoodName }
* dbo.Menu { ID, MenuName }
* dbo.FoodMenu { FoodID, MenuID }

I want to insert Food id and Menu id into FoodMenu table. My context is ok, my mapping is ok, codes and `Exception` below. Please help.

    public JsonResult FoodMenu(FoodMenuViewModel vm)
    {
        if (ModelState.IsValid)
        {
            ManyDbContext ctx = new ManyDbContext();

            foreach (var item in vm.MenuIds)
            {
                ctx.FoodMenus.Add(new FoodMenu { FoodID = vm.FoodId, MenuID = item });
                ctx.SaveChanges();
            }

            return Json(new { Result = true, Mesaj = "" });
        }
        else
        {
            return Json(new { Result = false, Mesaj = "" });
        }
    }

Exception:

> System.Data.Entity.Infrastructure.DbUpdateException: 'An error occurred while updating the entries. See the inner exception for details.'
> SqlException: Invalid object name '**dbo.FoodMenus**'.

Context:

            public DbSet<Food> Foods { get; set; }
            public DbSet<Menu> Menus { get; set; }
            public DbSet<FoodMenu> FoodMenus { get; set; }

Mapping:

    modelBuilder.Entity<Food>()
                .HasMany<Menu>(s => s.menus)
                .WithMany(c => c.foods)
                .Map(cs =>
                {
                    cs.MapLeftKey("FoodID");
                    cs.MapRightKey("MenuID");
                    cs.ToTable("FoodMenu");
                });

What I understand from this error is: my table's name is `dbo.FoodMenu` but exception says: it must be `dbo.FoodMenus`. Yet I don't know why.

ibrahim genc · Answer

I couldn't solve this problem. So I created two one to many mapping to insert into the FoodMenu table. one for Food and one for Menu. solved my problem, I can insert now. I do not have any problems in the get process too. My FoodMenu class; public class FoodMenu: AuditableEntity, IBaseDomain { public int FoodID { get ; set ; } public int MenuID { get ; set ; } public Food food { get ; set ; } public Menu menu { get ; set ; } } and mapping below; public FoodMenuMap() { ToTable( "FoodMenu" ); Property(x => x.FoodID).HasColumnName( "FoodID" ); Property(x => x.MenuID).HasColumnName( "MenuID" ); //One to Many FluentApi HasRequired (s => s.food) .WithMany(g => g.foodFoodMenus) .HasForeignKey int >(s => s.FoodID); HasRequired (s => s.menu) .WithMany(g => g.menuFoodMenus) .HasForeignKey int >(s => s.MenuID); } navigation properties of Food and Menu classes; Food: public List foodFoodMenus { get ; set ; } Menu: public List menuFoodMenus { get ; set ; }

ibrahim genc · Answer

here is my FoodMenu Table; namespace Many.Model.Domain { public class FoodMenu { [Key, Column(Order = 0)] public int FoodID { get; set; } [Key, Column(Order = 1)] public int MenuID { get; set; } } }

Madan Shekar · Answer

FoodMenus table contains any foreign key ?

ibrahim genc · Answer

The MenuIds is an int array, so item is int not an object. :(

Madan Shekar · Answer

i suspecting bellow code foreach (var item in vm.MenuIds) { ctx.FoodMenus.Add( new FoodMenu { FoodID = vm.FoodId, MenuID = item }); ctx.SaveChanges(); } actualy you have to pass menuid not object , so please try this one foreach (var item in vm.MenuIds) { ctx.FoodMenus.Add( new FoodMenu { FoodID = vm.FoodId, MenuID = item.MenuId}); ctx.SaveChanges(); } in case of any issues please let me know.

Madan Shekar · Answer

the issue is related to foreign key or referential intigrity