1.using ConsoleApplication42;using System.Data.Entity;using System.Data.Entity.ModelConfiguration.Conventions;namespace ConsoleApplication42{    using System;    using System.Collections.Generic;    using System.ComponentModel.DataAnnotations.Schema;    using System.Data.Entity;    using System.Linq;    public class TbUser    {        public int Id { get; set; }        public string UserName { get; set; }        public string Password { get; set; }        public string Email { get; set; }        public virtual ICollection<TbUserRole> TbUserRoles { get; set; }    }    public class TbRole    {        public int Id { get; set; }        public string RoleName { get; set; }        public string RoleDescription { get; set; }        public virtual ICollection<TbUserRole> TbUserRoles { get; set; }    }    public class TbUserRole    {        public int Id { get; set; }        public int UserId { get; set; }        public int RoleId { get; set; }        [ForeignKey("UserId")]        public virtual TbUser TbUser { get; set; }        [ForeignKey("RoleId")]        public virtual TbRole TbRole { get; set; }    }    public class MyDbContext : DbContext    {        public MyDbContext()            : base("MyDbContext")        {            if (Database.CreateIfNotExists())            {            }        }        public IDbSet<TbUser> TbUsers { get; set; }        public IDbSet<TbRole> TbRoles { get; set; }        public IDbSet<TbUserRole> TbUserRoles { get; set; }        protected override void OnModelCreating(DbModelBuilder modelBuilder)        {            //因为表名称默认为复数形式，这里是移除复数形式，所以为单数形式生成            modelBuilder.Conventions.Remove<PluralizingTableNameConvention>();        }    }    //public class MyEntity    //{    //    public int Id { get; set; }    //    public string Name { get; set; }    //}    public class Initializer : CreateDatabaseIfNotExists<MyDbContext>    {        public Initializer()        {        }        public override void InitializeDatabase(MyDbContext context)        {            base.InitializeDatabase(context);        }        protected override void Seed(MyDbContext context)        {            var tbUsers = new List<TbUser> {                new TbUser{UserName="张三",Password="zhangsan",Email="zhangsan@163.com"},                new TbUser{UserName="李四",Password="lisi",Email="lisi@163.com"}            };            tbUsers.ForEach(u => context.TbUsers.Add(u));            var tbRoles = new List<TbRole> {                new TbRole{RoleName="管理员",RoleDescription="管理员具有最高权限来对系统进行管理"},                new TbRole{RoleName="一般用户",RoleDescription="一般用户具有一些基本的操作权限"}            };            tbRoles.ForEach(r => context.TbRoles.Add(r));            var tbUserRole = new List<TbUserRole> {                new TbUserRole{UserId=1,RoleId=1},                new TbUserRole{UserId=1,RoleId=2},                new TbUserRole{UserId=2,RoleId=2}            };            tbUserRole.ForEach(ur => context.TbUserRoles.Add(ur));            context.SaveChanges();        }    }}2.<?xml version="1.0" encoding="utf-8"?><configuration>  <configSections>    <!-- For more information on Entity Framework configuration, visit http://go.microsoft.com/fwlink/?LinkID=237468 -->    <section name="entityFramework" type="System.Data.Entity.Internal.ConfigFile.EntityFrameworkSection, EntityFramework, Version=6.0.0.0, Culture=neutral, PublicKeyToken=b77a5c561934e089" requirePermission="false" />  </configSections>  <startup>    <supportedRuntime version="v4.0" sku=".NETFramework,Version=v4.5.2" />  </startup>  <entityFramework>    <contexts>      <context type="ConsoleApplication42.MyDbContext,ConsoleApplication42" disableDatabaseInitialization="false">        <databaseInitializer type="ConsoleApplication42.Initializer,ConsoleApplication42"></databaseInitializer>      </context>    </contexts>    <defaultConnectionFactory type="System.Data.Entity.Infrastructure.LocalDbConnectionFactory, EntityFramework">      <parameters>        <parameter value=http://www.mamicode.com/"mssqllocaldb" />      </parameters>    </defaultConnectionFactory>    <providers>      <provider invariantName="System.Data.SqlClient" type="System.Data.Entity.SqlServer.SqlProviderServices, EntityFramework.SqlServer" />    </providers>  </entityFramework>  <connectionStrings>    <add name="MyDbContext" connectionString="Data Source=(localdb)\ProjectsV13;Initial Catalog=People1;Integrated Security=True;Connect Timeout=30;Encrypt=False;TrustServerCertificate=True;ApplicationIntent=ReadWrite;MultiSubnetFailover=False" providerName="System.Data.SqlClient"/>  </connectionStrings></configuration>3.using System;using System.Collections.Generic;using System.Linq;using System.Text;using System.Threading.Tasks;namespace ConsoleApplication42{    class Program    {        static void Main(string[] args)        {            new MyDbContext();                    }    }}