ADO.NET数据查询方法

返回单一结果的查询方法

ExecuteScalar()方法的使用

 //编写连接字符串
            string connString = "Server=.;DataBase=StudentManageDB;Uid=sa;Pwd=aaa999a9";
            //创建连接对象
            SqlConnection conn = new SqlConnection(connString);
            //创建Command对象
            string sql = "select Count(*) from Students";
            SqlCommand cmd = new SqlCommand(sql, conn);
            //打开连接执行查询
            conn.Open();
            object result = cmd.ExecuteScalar();
            //关闭连接处理结果
            conn.Close();
            Console.WriteLine("学生总数"+result.ToString());
            Console.ReadLine();

string connString = "Server=.;DataBase=StudentManageDB;Uid=sa;Pwd=aaa999a9";
            SqlConnection conn = new SqlConnection(connString);

            string sql = "select StudentName from Students where StudentId=" + 10073;
            SqlCommand cmd = new SqlCommand(sql, conn);
            conn.Open();
            object result = cmd.ExecuteScalar();
            conn.Close();
            Console.WriteLine("学员姓名：{0}",result.ToString());
            Console.ReadLine();

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返回一个结果集的查询方法

ExecuteReader()方法

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返回多个结果集的查询方法

NextResult()方法

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