static void Main1(string[] args){//用户输入内容Console.WriteLine("请输入要查询的名称：");string str = Console.ReadLine();//造连接字符串string connstring = "server=.;database=mydb;user=sa;pwd=123";//造连接对象SqlConnection conn = new SqlConnection(connstring);//造命令对象SqlCommand cmd = conn.CreateCommand();//准备一条SQL语句cmd.CommandText = "select * from Info where Name like '%"+str+"%'";//打开连接
            conn.Open();//执行SQL语句SqlDataReader dr = cmd.ExecuteReader();//读取数据if (dr.HasRows){while (dr.Read()){int n = 0;while ( n <dr.FieldCount ) //.FieldCount获取当前行的列数
                    {Console.Write(dr[n]+"\t");n++;}Console.WriteLine();}}else{Console.WriteLine("没有查到满足条件的数据");}//关闭连接
            conn.Close();Console.ReadLine();}

static void Main4(string[] args){//用户输入要删除的数据主键值Console.WriteLine("请输入要删除的代号：");string code = Console.ReadLine();//判断该数据存不存在SqlConnection conn = new SqlConnection("server=.;database=mydb;user=sa;pwd=123");SqlCommand cmd = conn.CreateCommand();cmd.CommandText = "select * from Info where Code='"+code+"'";conn.Open();SqlDataReader dr = cmd.ExecuteReader();if (dr.HasRows){//说明该数据存在Console.WriteLine("查到该数据，是否要执行删除操作，如果要删除请输入：1");int sc = Convert.ToInt32(Console.ReadLine());if (sc == 1){//删除dr.Close(); //关闭读取器
cmd.CommandText = "delete from Info where Code='"+code+"'";cmd.ExecuteNonQuery();Console.WriteLine("删除成功！");}else{//不删除
                    dr.Read();string sex = Convert.ToBoolean(dr[2])?"男":"女";string nation = MinZu(dr[3].ToString());string str = "代号："+dr[0]+"\t姓名："+dr[1]+"\t性别："+sex+"\t民族："+nation+"\t生日："+dr[4];Console.WriteLine(str);}}else{//数据不存在Console.WriteLine("输入的代号错误！");}conn.Close();Console.ReadLine();}static string MinZu(string code){string name="";SqlConnection conn = new SqlConnection("server=.;database=mydb;user=sa;pwd=123");SqlCommand cmd = conn.CreateCommand();cmd.CommandText = "select Name from Nation where Code = '" + code + "'";conn.Open();SqlDataReader dr = cmd.ExecuteReader();if (dr.HasRows){dr.Read();name = dr[0].ToString();}conn.Close();return name;}

static void Main3(string[] args){//让用户输入要添加的内容Console.WriteLine("请输入要添加的代号：");string code = Console.ReadLine();Console.WriteLine("请输入姓名：");string name = Console.ReadLine();Console.WriteLine("请输入性别：");bool sex = Console.ReadLine()=="男"?true:false;Console.WriteLine("请输入民族：");string nation = Console.ReadLine();Console.WriteLine("请输入生日：");string birthday = Console.ReadLine();string nationcode = "n001";//将民族名称转为名族代号SqlConnection conn = new SqlConnection("server=.;database=mydb;user=sa;pwd=123");SqlCommand cmd = conn.CreateCommand();cmd.CommandText = "select Code from Nation where Name = '"+nation+"'";conn.Open();SqlDataReader dr = cmd.ExecuteReader();if (dr.HasRows){dr.Read();nationcode = dr[0].ToString();}conn.Close();//往Info表添加数据cmd.CommandText = "insert into Info values('"+code+"','"+name+"','"+sex+"','"+nationcode+"','"+birthday+"')";conn.Open();cmd.ExecuteNonQuery();conn.Close();Console.WriteLine("添加成功！");Console.ReadLine();}