create database guoji--建立数据库gouse guojigocreate table xinxi--建立表一(name varchar(20),minzu varchar(20))insert into xinxi values(‘lisi‘,‘101‘);insert into xinxi values(‘wangwu‘,‘102‘);insert into xinxi values(‘zhaoliu‘,‘103‘);select * from xinxigocreate table minz--建立表二(mcode varchar(20),mname varchar(20))insert into minz values(‘101‘,‘汉族‘);insert into minz values(‘102‘,‘满族‘);insert into minz values(‘103‘,‘藏族‘);goselect *  from minz

//进行xinxi表的实体化
using System;using System.Collections.Generic;using System.Linq;using System.Text;using System.Threading.Tasks;namespace biao.App_Code{    public class xinxi    {        private string _name;        public string name        {            get { return _name; }            set { _name = value; }        }        private string _minzu;        public string minzu//用这个接受数据        {            get { return _minzu; }            set { _minzu = value; }        }        public string minzustr//用这个输出数据        {            get             {                minzdata n = new minzdata();                string m = n.mname(_minzu);                return m;            }        }

//进行xinxi表的数据数据访问类using System;using System.Collections.Generic;using System.Linq;using System.Text;using System.Threading.Tasks;using System.Data.SqlClient;namespace biao.App_Code{    public class xinxidata    {        SqlConnection cnn = null;        SqlCommand cmd = null;        public xinxidata()        {            cnn = new SqlConnection("server=.;database=guoji;user=sa;pwd=123");            cmd = cnn.CreateCommand();        }        public List<xinxi> select()//查询全部信息，把信息放到集合里        {            xinxi x = null;            List<xinxi> list = new List<xinxi>();             cmd.CommandText = "select * from xinxi";            cnn.Open();            SqlDataReader ss = cmd.ExecuteReader();            if (ss.HasRows)            {                                while (ss.Read())                {                    x = new xinxi();                    x.name = ss["name"].ToString();                    x.minzu = ss["minzu"].ToString();                    list.Add(x);                }            }            else            {                Console.WriteLine("此表为空，没有数据！");            }            cnn.Close();            return list;        }

//minz表的实体化using System;using System.Collections.Generic;using System.Linq;using System.Text;using System.Threading.Tasks;namespace biao.App_Code{    public class minz    {        private string _mcode;        public string mcode        {            get { return _mcode; }            set { _mcode = value; }        }        private string _mname;        public string mname        {            get { return _mname; }            set { _mname = value; }        }    }}

//minz表的数据访问类using System;using System.Collections.Generic;using System.Linq;using System.Text;using System.Threading.Tasks;using System.Data.SqlClient;namespace biao.App_Code{    public class minzdata    {        SqlConnection cnn = null;        SqlCommand cmd = null;        public minzdata()        {            cnn = new SqlConnection("server=.;database=guoji;user=sa;pwd=123");            cmd = cnn.CreateCommand();        }        public string mname(string code)//根据编号查姓名        {                        string a = "<无>";            cmd.CommandText = "select * from minz where mcode=@a";            cmd.Parameters.Clear();            cmd.Parameters.Add("@a",code);            cnn.Open();            SqlDataReader ss = cmd.ExecuteReader();            if (ss.HasRows)//是否有这个数据            {                ss.Read();                a = ss[1].ToString();                            }            else            {                Console.WriteLine("数据表为空");            }                       cnn.Close();            return a;        }    }}

//在program类的主函数using System;using System.Collections.Generic;using System.Linq;using System.Text;using System.Threading.Tasks;using biao.App_Code;namespace biao{    class Program    {        static void Main(string[] args)        {            xinxidata a = new xinxidata();            List<xinxi> list = a.select();            foreach (xinxi b in list)//遍历集合查询全部内容            {                Console.WriteLine(b.name + "  " + b.minzustr);//用b.minzustr输出语句            }            Console.ReadLine();        }    }}