ADO.NET 增删改查
2010-12-04 18:28:45| 分类： ado.net | 标签： |举报 |字号大中小 订阅 sql
查询
using System;
using System.Collections.Generic;
using System.Linq;
using System.Text;
using System.Data.SqlClient;
namespace ado1
{
class Program
{
//单例模式
public static SqlConnection dbconn = null;
static void Main(string[] args)
{
Insert ins = new Insert();
ins.add();
/*
SqlCommand dbCmd = null
;//SqlCommand 对象主要能够用来对数据库发出一些指令，例如能够对数据库下达查询、新增、修改、删除数据等指令，以及呼叫存在数据库中的预存程序等。这个对象是架构在Connection 对象上，也就是Command 对象是透过连结到数据源
SqlDataReader dbReader = null
;//当咱们只须要循序的读取数据而不须要其它操做时，能够使用DataReader 对象。
string strSql = "select * from t_user ";
Program pg = new Program();
//这里用using直接释放 conn 不用手动关闭了
using (pg.getConn
())//这里表明得到链接
{
dbconn.Open();
using( dbCmd = dbconn.CreateCommand()){//同理
dbCmd.CommandText = strSql;
using (dbReader=dbCmd.ExecuteReader())//同理
{
while (dbReader.Read())
{
Console.WriteLine("id号:" + " " + dbReader.GetInt32(dbReader.GetOrdinal("id")));//
依据列名打印
Console.WriteLine("姓名:" + " " + dbReader.GetString(dbReader.GetOrdinal("name")));
Console.WriteLine("年龄:" + " " + dbReader.GetInt32(dbReader.GetOrdinal("age")));
}
}
}
}
Console.ReadKey();*/
}
//得到链接
public SqlConnection getConn() {
if (dbconn == null)
{
string strConn = "Data Source=.;Initial Catalog=guchao;Integrated Security=True";
dbconn = new SqlConnection(strConn);
return dbconn;
}
return dbconn;
}
--------
增删改
class Insert
{
public static SqlConnection dbconn = null;
public void add()
{
//Insert ins = new Insert();
SqlConnection dbConn = null;
SqlCommand dbCmd = null;
//string strSql = "insert into t_user (name,age)values('guchaojimmy','25') ";
string strSql = "update t_user set name = @username where id =" + 3;//防止sql注入起别名
//string strSql = "delete from t_user where id = "+4;
Program pg = new Program();
using (pg.getConn())
{
dbconn.Open();
using( dbCmd = dbconn.CreateCommand()){
dbCmd.CommandText = strSql;
dbCmd.Parameters.Add(new SqlParameter("username","changying"));//防止sql注入
dbCmd.ExecuteNonQuery();//nonquery 就是否是 查询 这里是添加 修改和删除都用这个方法 } } Console.ReadKey(); } public SqlConnection getConn() { if (dbconn == null) { string strConn = "Data Source=.;Initial Catalog=guchao;Integrated Security=True"; dbconn = new SqlConnection(strConn); return dbconn; } return dbconn; } } } } }