![](/img/trans.png)
[英]How do I update a table with LINQ-to-SQL without having to delete all the existing records?
[英]How can I Update and delete records in my database by LINQ to SQL?
有做這項工作的能力嗎? 我該怎么做?
當您使用DataContext生成LINQ to SQL查詢時,它將跟蹤從該上下文中退出的查詢中選擇的對象。
話雖這么說,如果您對返回的對象進行更改,然后在DataContext實例上調用SubmitChanges方法 ,則更改將被持久化回到基礎數據存儲中。
如果要刪除對象,則將對象傳遞給Table<T>
實例上的DeleteOnSubmit方法 (其中T是數據庫中表的模型的類型)。 然后,當您在DataContext上調用SubmitChanges時,將刪除傳遞給DeleteOnSubmit方法的模型所表示的記錄。
var context = new MyDataContext(); var newObj = new User(); newObj.UserID = 1; newObj.Name =“ Ted”;
context.Users.InsertOnSubmit(newObj); //queues for submission
context.SubmitChanges(); //submits to backend
或更新:
var context = new MyDataContext();
var user = context.Users.First(i => i.UserID = 1);
//entities self aware and automatically synced to database when a value changes
user.Name = "Dave";
context.SubmitChanges(); //knows about updated record
聲明:本站的技術帖子網頁,遵循CC BY-SA 4.0協議,如果您需要轉載,請注明本站網址或者原文地址。任何問題請咨詢:yoyou2525@163.com.