C#笔记 ADO.NET操作SQL SERVER数据库

      本文演示在C#中使用ADO.NET组件连接SQL SERVER 2005数据库文件，并对其中的数据表进行相应的操作。涉及的数据存取对像有SqlConnection、SqlCommand、SqlDataAdapter、SqlDataReader，还有临时的数据表存储对象DataSet。具体的使用方法，大家可以参考下面的代码自己体会一下。
      注意：需要引用命名空间System.Data.SqlClient
      控制数据流的类DataProcess:     

 class DataProcess
    {
        static string conn = "Data source=.;Initial Catalog=test;Integrated Security=true";
        string sql = "";

        List<Student> studentList = new List<Student>();
        DataSet ds = new DataSet();

        SqlConnection sqlConn = new SqlConnection(conn);
        SqlCommand command;

        public void OpenConnection()
        {
            sqlConn.Open();
        }
        public void CloseConnection()
        {
            sqlConn.Close();
        }

        public void ShowWelcome()
        {
            Console.WriteLine("   " + "学生成绩维护");
            Console.WriteLine("====================");
            Console.WriteLine("     L 显示");
            Console.WriteLine("     A 增加");
            Console.WriteLine("     D 删改");
            Console.WriteLine("     E 修改");
            Console.WriteLine("     Q 退出");
        }

        public void StudentList(string tableName)
        { 
            string sql = "select * from " + tableName;
            SqlDataAdapter da = new SqlDataAdapter(sql, sqlConn);
            da.Fill(ds, "成绩表");    

            //PadRight使字符个数为定长,用来控制显示形式
            //这里将int型变量前置，完全是为了显示结果的美观
            Console.WriteLine("学号".PadRight(8) + "成绩".PadRight(8) + "姓名".PadRight(8));
            for (int i = 0; i < ds.Tables[0].Rows.Count; i++)
            {
                string stuNum = ds.Tables[0].Rows[i][0].ToString();
                string name = ds.Tables[0].Rows[i][1].ToString();
                string grade= ds.Tables[0].Rows[i][2].ToString();
                Console.WriteLine(stuNum.PadRight(10) + grade.PadRight(10) + name.PadRight(10));
            }
            ds.Tables[0].Clear();                       
        }

        //添加学生信息
        public void Add()
        {
            Console.WriteLine("请输入学生编号：");
            int stuNum = int.Parse(Console.ReadLine());
            Console.WriteLine("请输入学生姓名：");
            string name = Console.ReadLine();
            Console.WriteLine("请输入学生成绩：");
            int grade = int.Parse(Console.ReadLine());
            sql=string.Format("insert into 成绩表(学号,姓名,成绩)  values({0},'{1}',{2})",stuNum,name,grade);
            //实例化command对象，用于执行SQL非查询操作
            command = new SqlCommand(sql, sqlConn);
            command.ExecuteNonQuery();
            Console.WriteLine("数据插入成功!");
        }

        //删除学生信息
        public void Delete()
        {
            Console.WriteLine("请输入学生编号");
            string stuNum = Console.ReadLine();
            sql = "select * from 成绩表 where 学号="+stuNum;
            command = new SqlCommand(sql, sqlConn);
            SqlDataReader sdr = command.ExecuteReader();
            Console.WriteLine("学号".PadRight(8) + "成线".PadRight(8) + "姓名".PadRight(8));
            while (sdr.Read())
            {
                Console.WriteLine(sdr[0].ToString().PadRight(10)+sdr[2].ToString().PadRight(10)+sdr[1].ToString().PadRight(10));
            }
            sdr.Close();
            sql = "delete from 成绩表 where 学号="+stuNum;
            command = new SqlCommand(sql, sqlConn);
            command.ExecuteNonQuery();
            Console.WriteLine("学生信息已删除！");
        }

        public void Modify()
        {
            Console.WriteLine("请输入学生编号");
            string stuNum = Console.ReadLine();
            sql = "select * from 成绩表 where 学号=" + stuNum;
            command = new SqlCommand(sql, sqlConn);
            SqlDataReader sdr = command.ExecuteReader();
            Console.WriteLine("学号".PadRight(8) + "成线".PadRight(8) + "姓名".PadRight(8));
            while (sdr.Read())
            {
                Console.WriteLine(sdr[0].ToString().PadRight(10) + sdr[2].ToString().PadRight(10) + sdr[1].ToString().PadRight(10));
            }
            sdr.Close();
            Console.WriteLine("请输入学生姓名：");
            string name = Console.ReadLine();
            Console.WriteLine("请输入学生成绩：");
            string grade = Console.ReadLine();
            sql = string.Format("update 成绩表 set 姓名='{0}',成绩={1} where 学号={2}",name,grade,stuNum);
            command = new SqlCommand(sql, sqlConn);
            command.ExecuteNonQuery();
            Console.WriteLine("学生信息修改成功！");        
        }
    }

上面的类中，List泛型创建的对象其实是没用的，上载时自己疏忽了。（-_-）！！！呵呵。
      控制台的显示：

class Program
    {
        static void Main(string[] args)
        {
            DataProcess dp = new DataProcess();
            dp.ShowWelcome();            
            while (true)
            {
                ConsoleKeyInfo cki = new ConsoleKeyInfo();
                cki = Console.ReadKey(true);
                switch (char.ToUpper(cki.KeyChar))
                {
                    case 'L':
                        dp.OpenConnection();
                        dp.StudentList("成绩表");
                        dp.CloseConnection();
                        break;
                    case 'A':
                        dp.OpenConnection();
                        dp.Add();
                        dp.CloseConnection();
                        break;
                    case'D':
                        dp.OpenConnection();
                        dp.Delete();
                        dp.CloseConnection();
                        break;
                    case'E':
                        dp.OpenConnection();
                        dp.Modify();
                        dp.CloseConnection();
                        break;
                    default:
                        dp.ShowWelcome();
                        break;
                }
            }
        }
    }