ModelBuilder 的命名空间是哪个？解决办法

ModelBuilder 的命名空间是哪个？
我百度了下也没有找到


错误1未能找到类型或命名空间名称“ModelBuilder”(是否缺少 using 指令或程序集引用?)C:\Users\Administrator\Documents\Visual Studio 2010\Projects\MvcMovie\MvcApplication1\Models\Movie.cs2749MvcMovie

C# code

using System;using System.Collections.Generic;using System.Linq;using System.Web;using System.Data.Entity;using System.Data.Entity.ModelConfiguration;namespace MvcApplication1.Models{    public class Movie    {            public int ID { get; set; }            public string Title { get; set; }            public DateTime ReleaseDate { get; set; }            public string Genre { get; set; }            public decimal Price { get; set; }            public string Rating { get; set; }    }    public class MovieDBContext : DbContext    {        public DbSet<Movie> Movies { get; set; }        protected override void OnModelCreating(ModelBuilder modelBuilder)        {            modelBuilder.Entity<Movie>().Property(p =>p.Price).HasPrecision(18, 2);        }    }}