问EF DB在添加代码生成项目时首次生成错误

EN

//------------------------------------------------------------------------------
/ <auto-generated>
//     This code was generated from a template.
//
//     Manual changes to this file may cause unexpected behavior in your application.
//     Manual changes to this file will be overwritten if the code is regenerated.
// </auto-generated>
//------------------------------------------------------------------------------

namespace project.DAL
{
    using System;
    using System.Data.Entity;
    using System.Data.Entity.Infrastructure;

    public partial class NebulabEntities : DbContext
    {
        public NebulabEntities()
            : base("name=NebulabEntities")
        {
        }

        protected override void OnModelCreating(DbModelBuilder modelBuilder)
        {
            throw new UnintentionalCodeFirstException();
        }

        public virtual DbSet<Commodity> Commodities { get; set; }
        public virtual DbSet<CommoditiesPrice> CommoditiesPrices { get; set; }

     }
}

Severity    Code    Description Project File    Line
Error   CS0426  The type name 'Data' does not exist in the type 'System'    project.DAL C:\Test\project.DAL\RedSpiderDataModel.Context.cs   13
Error   CS0426  The type name 'Data' does not exist in the type 'System'    project.DAL C:\Test\project.DAL\RedSpiderDataModel.Context.cs   14
Error   CS0246  The type or namespace name 'DbContext' could not be found (are you missing a using directive or an assembly reference?) project.DAL C:\Test\project.DAL\RedSpiderDataModel.Context.cs   16
Error   CS0115  'NebulabEntities.OnModelCreating(DbModelBuilder)': no suitable method found to override project.DAL C:\Test\project.DAL\RedSpiderDataModel.Context.cs   23
Error   CS0246  The type or namespace name 'DbModelBuilder' could not be found (are you missing a using directive or an assembly reference?)    project.DAL C:\Test\project.DAL\RedSpiderDataModel.Context.cs   23
Error   CS0246  The type or namespace name 'DbSet<Commodity>' could not be found (are you missing a using directive or an assembly reference?)  project.DAL C:\Test\project.DAL\RedSpiderDataModel.Context.cs   28
Error   CS0246  The type or namespace name 'DbSet<CommoditiesPrice>' could not be found (are you missing a using directive or an assembly reference?)   project.DAL C:\Test\project.DAL\RedSpiderDataModel.Context.cs   29