Windows Phone 7.5-本地SQL数据库 [英] Windows Phone 7.5 - Local SQL Database

问题描述

我正在创建WP7应用.

I am creating WP7 app.

在那个应用程序中，我使用LINQ to SQL创建本地数据库.我创建了一个像这样的类:

In that app i am using LINQ to SQL to create local database. I have created a class like this:

[Table]
public class User
{
    [Column(
        IsPrimaryKey = true,
        IsDbGenerated = true,
        DbType = "INT NOT NULL Identity",
        CanBeNull = false)]
    public int Id { get; set; }

    [Column]
    public string FirstName { get; set; }

    [Column]
    public string LastName { get; set; }     
}

并且我有如下数据上下文:

and I have data context like below:

public class UserDataContext : DataContext
    {
        public static string connString = "Data Source=isostore:/Users.sdf";

        public UserDataContext(string connString)
            : base(connString)
        { }

        public Table<User> Users;
    }

我正在使用以下代码保存数据:

I am saving the data using below code:

User user = new User
            {
                FirstName = tbFirstName.Text,
                LastName = tbLastName.Text,
                CreatedOn = DateTime.Now
            };
using (var db = new UserDataContext(UserDataContext.connString))
            {
                db.Users.InsertOnSubmit(user);
                db.SubmitChanges();
            }

但是这里我的问题是:在保存用户列表时，有诸如保存1天" ，"30天" 或永远"之类的单选框. 如果我选择一天"，我必须将其保存1天，那么一天后应从本地数据库中删除用户；如果我选择"30天"，则应在30天后将其删除，如果我选择永远" 它不应被删除.

But here my problem is: While saving the user list there is radioboxes like "Save for 1 Day", "30 days" or "forever". If i select "one day" i have to save it for 1 day then users from local database should be deleted after one day and if i select "30 days" it should be deleted after 30 days and if i select "forever" it should not be deleted.

我该怎么做?

提前谢谢.

推荐答案

我将在表中添加另一列(有效期). 然后，我将通过一个简单的查询清除数据

I would add another column to the table(expiry date). And then, I would purge data with a Simple query

DELETE FROM User    
WHERE (expiryDate < GETDATE())

您也可以在Linq2Sql中做到这一点

You can do this in Linq2Sql as well

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