EF使用Code First模式给实体类添加复合主键

using System;
using System.Collections.Generic;
using System.ComponentModel.DataAnnotations;
using System.ComponentModel.DataAnnotations.Schema;
using System.Linq;
using System.Web;

namespace MyFirstMvcApp.Models
{
    /// <summary>
    /// 登录记录
    /// </summary>
    public class LoginRecordInfo
    {
        /// <summary>
        /// 登录的邮件地址（主键）
        /// </summary>
        [Key,Column(Order=1)]
        public string Email { get; set; }

        /// <summary>
        /// 登录的客户端IP
        /// </summary>
        public string LoginHostIP { get; set; }

        /// <summary>
        /// 登录的客户端主机名
        /// </summary>
        public string LoginHostName { get; set; }

        /// <summary>
        /// 登录时间（主键）
        /// </summary>
        [Key,Column(Order=2)]
        public DateTime LoginTime { get; set; }
    }
}