操作数据库数据

using System;
using System.Collections.Generic;
using System.Data;
using System.Data.SqlClient;
using System.Linq;
using System.Text;
using System.Threading.Tasks;

/*
 *名称：连接数据库
 *日期：2017.07.13
 */
namespace Data
{
    class Program
    {
        static void Main(string[] args)
        {
            //连接数据库
            string connstring = "server = .; database = Demo1;uid = sa;pwd = 123456";
            SqlConnection conn = new SqlConnection(connstring);
            //打开数据库
            conn.Open();
            //第一部分：
            //查询
            String sql = "select * from ClassTable";
            SqlCommand command = new SqlCommand(sql, conn);//检索对象
            SqlDataReader dr = command.ExecuteReader();//读取数据对象
            while (dr.Read())
            {
                Console.WriteLine("Id:{0} ClassCode:{1} ClassName:{2}", dr["Id"], dr["ClassCode"], dr["ClassName"]);
            }
            dr.Close();//关闭DataRead
            //添加
            string addSql = "insert into StudentTable(StudentCode,StudentName) values ('SC1021','张三')";
            command = new SqlCommand(addSql, conn);
            command.ExecuteNonQuery();
            //更新
            string upDataSql = "update StudentTable set StudentName = '小王' where Id = 2";
            command = new SqlCommand(upDataSql, conn);
            command.ExecuteNonQuery();
            //删除
            string deleteSql = "delete from StudentTable where Id = 21";
            command = new SqlCommand(deleteSql, conn);
            command.ExecuteNonQuery();
            //第二部分:
            //dataAdapter
            //查询
            SqlDataAdapter adapter = new SqlDataAdapter(command);
            DataSet dataSet = new DataSet();
            adapter.Fill(dataSet);
            foreach(DataRow r in dataSet.Tables[0].Rows){
                Console.WriteLine("Id:{0} ClassCode:{1} ClassName:{2}", r["Id"], r["ClassCode"], r["ClassName"]);
            }
            //更新数据
            SqlCommandBuilder scb = new SqlCommandBuilder(adapter);//dataSet 与 数据库 更新协调
            dataSet.Tables[0].Rows[0]["ClassCode"] = "CC1010";
            adapter.Update(dataSet);//更新数据
            
            //关闭数据库
            conn.Close();
            Console.ReadKey();
            
        }
    }
}