問題描述

在我的數(shù)據(jù)庫中，我有一個(gè)名為 question1 的表，初始默認(rèn)狀態(tài)分配為 = 0，然后每次我想更新時(shí)我都希望狀態(tài) = 1，我使用命令

In my database I have table named question1, with the initial default status assigned = 0, then every time I want to update I want the status = 1, I use the command

await conn.ExecuteAsync("UPDATE question1 SET Status = '1' WHERE id =" + ques1.id);

但它不起作用.誰知道這里出了什么問題?下面是讀取數(shù)據(jù)和更新表的代碼......

but it is not working. Who knows what is wrong here? Here's the code to read the data and update the table......

public async Task<question1> get_data_question1()
{
    SQLiteAsyncConnection conn = new SQLiteAsyncConnection("Database");
    var query = conn.Table<question1>().Where(x => x.Status == 0);
    var result = await query.ToListAsync();
    question1 ques1 = new question1();
    foreach (var item in result)
    {
        ques1.id = item.id;
        ques1.Status = item.Status;
    }
    // Update
    await conn.ExecuteAsync("UPDATE question1 SET Status = '1' WHERE id =" + ques1.id);
    return ques1;
}

推薦答案

這就是我設(shè)置簡單數(shù)據(jù)庫的方式.

This is how I would set up your simple database.

它將創(chuàng)建 3 個(gè)條目，所有狀態(tài) = 0.

It will create 3 entries with all Status = 0.

在代碼中我說的那一行處設(shè)置一個(gè)斷點(diǎn)；

Put a break point at the line where I said so in the code;

您會(huì)在該查詢之后看到所有 0 值都已更新為 1.

You will see after that query all 0 values has been updated to 1.

using SQLite;
using System.IO;
using System.IO.IsolatedStorage;
using System.Threading.Tasks;

public class Question
{
    [SQLite.PrimaryKey, SQLite.AutoIncrement]
    public int Id { get; set; }
    public int Status { get; set; }
} 

public partial class MainPage : PhoneApplicationPage
{
    string dbPath = "";
    public MainPage()
    {
        InitializeComponent();
        dbPath = Path.Combine(Windows.Storage.ApplicationData.Current.LocalFolder.Path, "db.sqlite");                        

        CreateDBTable();
        InsertDB();         // only call this once (comment it out the next time you deploy)
        UpdateDB();

    }
}

// from the MSDN example
private async Task<bool> FileExists(string fileName)
{
    var result = false;
    try
    {
        var store = await Windows.Storage.ApplicationData.Current.LocalFolder.GetFileAsync(fileName);
        result = true;
    }
    catch
    {
    }
    return result;
}

public void CreateDBTable()
{
    if (!FileExists("db.sqlite").Result)
    {
        using (var db = new SQLiteConnection(dbPath))
        {
            db.CreateTable<Question>();
        }
    } 
}

public void UpdateDB()
{
    using (var db = new SQLiteConnection(dbPath))
    {
        var existing = db.Query<Question>("SELECT * FROM Question WHERE Status = 0");
        if (existing != null)
        {
            foreach(Question q in existing)
            {
                db.Execute("UPDATE Question SET Status = 1 WHERE Id = ?", q.Id);
            }
        }


        // query again to see if has changed
        existing.Clear();

        existing = db.Query<Question>("SELECT * FROM Question WHERE Status = 1");
        if (existing != null)
        {
            int breakpoint_here = 1;
        }

    } 
}

private void InsertDB()
{
    using (var db = new SQLiteConnection(dbPath))
    {
        db.RunInTransaction(() =>
        {
            db.Insert(new Question() { Status = 0 });
            db.Insert(new Question() { Status = 0 });
            db.Insert(new Question() { Status = 0 });
        });
    }
}

這篇關(guān)于Sqlite Window Phone 8 中的更新記錄的文章就介紹到這了，希望我們推薦的答案對(duì)大家有所幫助，也希望大家多多支持html5模板網(wǎng)！