雖然接觸微軟的東西時間不長,但對於orm這塊,自己認爲 Linq to sql 比起hibernate 要有優勢,對於中小型系統,它會更活躍。不要去管微軟要不要放棄 Linq to sql ,它現在能滿足我的需求,而且好用,這就足夠了。微軟是不可能放棄對它的支持的。
出處:http://www.cnblogs.com/greatverve/archive/2010/05/13/1734236.html
尊敬知識,尊敬作者是種美德
1.接上篇http://www.cnblogs.com/greatverve/archive/2010/05/12/1733513.html
在Northwind下新建表t_User
ID,
int,主鍵,自增。
UserName, varchar(50)
Pwd,
varchar(50)
2.從服務器資源管理器中把t_User拖到Northwind.dbml中。
即生成orm映射。
3.增刪改查的代碼參考下面的Linq3();
using System.Collections.Generic;
using System.Linq;
using System.Web;
using System.Web.UI;
using System.Web.UI.WebControls;
using System.Data.Common;
using System.Collections.Generic;
namespace FirstLinq
{
public partial class _Default : System.Web.UI.Page
{
NorthwindDataContext ctx = new NorthwindDataContext("Data Source=ZHANGSHUQIANG;Initial Catalog=Northwind;Persist Security Info=True;User ID=sa;Password=sa");
protected void Page_Load(object sender, EventArgs e)
{
Linq1();
Linq2();
Linq3();
}
///
/// 增刪改查
///
private void Linq3()
{
//增
t_User user = new t_User();
user.UserName = "大氣象";
user.Pwd = "123456";
ctx.t_User.InsertOnSubmit(user);//以前的方法是Add();
ctx.SubmitChanges();
//改
//參考這樣的語法string s = (from a in ctx.Customers select a).Single(a => a.ID == 2);
t_User userUpdate = ctx.t_User.SingleOrDefault(t_User => t_User.ID == 2);//Single與SingleOrDefault沒區別
userUpdate.UserName = "大氣象1";
ctx.SubmitChanges();
//刪
t_User userDelete = (from userinfo in ctx.t_User where userinfo.ID == 1 select userinfo).FirstOrDefault();
if (userDelete != null)
{
ctx.t_User.DeleteOnSubmit(userDelete);
ctx.SubmitChanges();
}
}
///
/// 熟悉Linq to sql語法
///
private void Linq2()
{
Customers customer = new Customers();
//執行普通的sql語句,查詢CustomerID="ANATR"的記錄
IEnumerable<</span>Customers> customers = ctx.ExecuteQuery<</span>Customers>("select * from Customers where CustomerID='ANATR'");
customer = customers.First();
Response.Write(customer.CustomerID);
//使用Linq查詢單條記錄
var cus = from c in ctx.Customers where c.CustomerID.Equals("ANATR") select c;
customer = cus.First();
Response.Write(customer.CompanyName);
//查詢結果集,語法:from 臨時表名 in 表集合 orderby 臨時表名.字段名 升級序 select 臨時表名
gdvCustomers.DataSource = from cust in ctx.Customers where cust.CustomerID != "ANATR" orderby cust.CompanyName descending select cust;
gdvCustomers.DataBind();
}
///
/// 熟悉一下linq語法,變量的定義類似js,無須聲明類型。
///
private void Linq1()
{
var age = 29;
var username = "greatverve";
var userlist = new[] { "a", "b", "c" };
foreach (var user in userlist)
{
Response.Write(user);
}
}
}
}
參考:
http://www.cnblogs.com/webabcd/archive/2007/10/18/928353.html
http://www.cnblogs.com/lovecherry/archive/2007/08/16/858009.html