半城柳色半声笛

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半城柳色半声笛 2024-11-20 21:56:41

是的,您可以根据需要多次加入表。

SELECT 
  sender.ID AS `sender_id`, 
  sender.Name AS `sender_name`, 
  receiver.ID AS `receiver_id`, 
  receiver.Name AS `receiver_name`, 
  Messages.Message
FROM
  Messages
INNER JOIN
  Users AS sender
ON
  sender.ID = Messages.Sender
INNER JOIN
  Users AS receiver
ON
  receiver.ID = Messages.Receiver

Yes, you can join the tables as many times as needed.

SELECT 
  sender.ID AS `sender_id`, 
  sender.Name AS `sender_name`, 
  receiver.ID AS `receiver_id`, 
  receiver.Name AS `receiver_name`, 
  Messages.Message
FROM
  Messages
INNER JOIN
  Users AS sender
ON
  sender.ID = Messages.Sender
INNER JOIN
  Users AS receiver
ON
  receiver.ID = Messages.Receiver

在 MySQL 中连接两个表两次。可能还是不可能???

半城柳色半声笛 2024-11-20 12:15:39

尝试使用类似 nohup 的工具在远程服务器上启动节点进程。

bash$ nohup /path/to/node server.js > out.txt 2> err.txt &
[1] 53032
# Now you can logout of the remote server without
#   killing the "node" process and chat server.

[编辑]

请注意,“nohup”打印的数字(例如 53032)是分离进程的 ID,因此如果您需要终止它,可以执行类似“kill -9 53032”的操作”。如果您忘记记录该号码,则必须使用“ps”等程序来查找它;例如,您可以运行“ps auxwww | grep node”(标志将根据您的系统而有所不同),您将看到与此类似的输出:

maerics  81694   0.6  0.5  2543604  21216 s000  S+   10:34AM   0:09.45 /Users/maerics/opt/node/node server.js

在此示例中,在我的系统上,数字第二列是进程 ID。

Try launching your node process on the remote server using a tool like nohup.

bash$ nohup /path/to/node server.js > out.txt 2> err.txt &
[1] 53032
# Now you can logout of the remote server without
#   killing the "node" process and chat server.

[Edit]

Note that the number printed by "nohup" (e.g. 53032) is the id of detached process, so if you need to terminate it you can do something like "kill -9 53032". If you forgot to record that number then you'll have to find it by using a program such as "ps"; for example, you can run "ps auxwww | grep node" (the flags will vary depending on your system) and you'll see output similar to this:

maerics  81694   0.6  0.5  2543604  21216 s000  S+   10:34AM   0:09.45 /Users/maerics/opt/node/node server.js

In this example, on my system, the number in the second column is the process id.

Nodejs 服务器 - Mac 终端每隔一小时崩溃一次

半城柳色半声笛 2024-11-20 11:27:01

就在今天,我遇到了类似的情况(但在其他情况下,我试图从数据库创建实体)。

我解决了这个问题,只需将parameters.ini文件中的database_host“localhost”修改为“127.0.0.1”

我认为我的 Mysql 实例仅通过 TCP 而不是套接字运行,因为当使用 database_host="localhost" 时它会失败。

Just today I had a similar situation (but in other context, I was trying to create entities from db).

I solved it simply modifying the database_host from "localhost" to "127.0.0.1" in the parameters.ini file.

I think my Mysql instance is running only via TCP and not socket and because this when use database_host="localhost" it fails.

解决“没有这样的文件或目录”的问题运行 `php app/console 学说:schema:create` 时

半城柳色半声笛 2024-11-20 09:12:45

它们称为属性。它们对于提供有关类的元数据(有关数据的数据)非常有用。

They are called attributes. They are quite useful for providing metadata about the class (data about the data).

帮助理解 C# 中此语句的语法

半城柳色半声笛 2024-11-20 08:16:17

在处理提交的操作中设置断点并检查值列表的属性。如果它为空或为空,则重新加载它。

如果您的下拉列表是通过 JavaScript 填充的,则保存值列表的属性在提交时可能为空。在使用级联下拉列表时,这种情况很常见,例如加载基于国家/地区的省/州列表的情况。模型传递到视图后加载的所有级联列表必须使用处理提交的控制器操作中每个下拉列表的选定值重新加载。

Set a breakpoint in the action handling the submission and check the property for the list of values. If it's null or empty reload it.

If your dropdownlist is being populated via javascript then it is possible that the property holding the list of values is empty on submission. This is common when using cascading dropdownlists such is the case with loading Province / State lists based off country. All cascading lists loaded after the model has been passed to the view must be reloaded using the selected value of for each dropdownlist in the controller action that is handling the submission.

验证失败时选定的 Dropdown 值发生变化 - ASP.NET MVC

半城柳色半声笛 2024-11-20 06:56:46

动画完全支持 x 文件格式,此外,当您想使用着色器时,它还支持 fx 文件。您可以从此页面下载导出器插件和示例:

http://www.cgdev.net/download.php

Animation is full supported in x file format, and furthermore, it support fx files when you want to use shaders. A exporter plugin and samples you can download from this page:

http://www.cgdev.net/download.php

将网格从 .obj(或任何其他)文件加载到 DirectX9/C++项目

半城柳色半声笛 2024-11-20 05:45:53
Class myclass = ClassLoader.getSystemClassLoader().loadClass("package.MyClass");

或者

Class myclass  = Class.forName("package.MyClass");

从不在类路径中的不同文件夹加载类:

File f = new File("C:/dir");
URL[] cp = {f.toURI().toURL()};
URLClassLoader urlcl = new URLClassLoader(cp);
Class myclass  = urlcl.loadClass("package.MyClass");

为了进一步使用加载的类,如果加载的类不在类路径中并且无法导入和转换它,则可以使用反射。例如,如果您想调用名为“main”的静态方法:

Method m = myclass.getMethod("main", String[].class);
String[] args = new String[0];
m.invoke(null, args);  // invoke the method
Class myclass = ClassLoader.getSystemClassLoader().loadClass("package.MyClass");

or

Class myclass  = Class.forName("package.MyClass");

or loading the class from different folder which is not in the classpath:

File f = new File("C:/dir");
URL[] cp = {f.toURI().toURL()};
URLClassLoader urlcl = new URLClassLoader(cp);
Class myclass  = urlcl.loadClass("package.MyClass");

For further usage of the loaded Class you can use Reflection if the loaded Class is not in your classpath and you can not import and cast it. For example if you want to call a static method with the name "main":

Method m = myclass.getMethod("main", String[].class);
String[] args = new String[0];
m.invoke(null, args);  // invoke the method

动态加载java类文件的方法

半城柳色半声笛 2024-11-20 04:34:21

检查gem list的输出。如果 sqlite gem 不在其中,那么您需要安装它。

对于 Rails 3,您需要在 Gemfile 中添加以下内容:

gem 'sqlite'

...然后运行:

bundle install

对于 Rails 2 运行:

gem install sqlite

Check the output of gem list. If the sqlite gem is not in there then you need to install it.

For Rails 3 you need to add the following in your Gemfile:

gem 'sqlite'

... then run:

bundle install

For Rails 2 run:

gem install sqlite

ruby on Rails 的 sqlite3 安装位置

半城柳色半声笛 2024-11-18 16:38:08

是的,您可以下载 .ppt、word 文件并将其保存在应用程序包中。
您可以使用 UIWebView 打开文档。

使用 UIWebView 显示选定的文档类型

Yes, you can download the .ppt , word file and save that in your application bundle.
and you could open the Docs with UIWebView .

Using UIWebView to display select document types

从自定义 iOS 应用程序启动 msoffice 文档查看器

半城柳色半声笛 2024-11-18 15:15:23

您必须确保仅在用户启动的事件处理程序(通常是页面中的“单击”事件)内发出文件下载的 HTTP 请求。 (实际上可能只有点击事件起作用;我没有费心去调查,因为无论如何几乎总是涉及“点击”。)

您无法阻止浏览器以这种方式运行。

You have to make sure that you issue an HTTP request for a file download only within a user-initiated event handler, generally a "click" event from the page. (It may in fact be that only click events work; I've not bothered to investigate since there's almost always a "click" involved anyway.)

You cannot prevent the browser from behaving that way.

当 ie7 和 ie8 说“帮助保护您的 bla bla”时,我如何才能意识到?因为它阻止我的 servlet 将字节数组作为下载文件提供服务

半城柳色半声笛 2024-11-18 14:43:44
使用 System.Globalization;

字符串文化 = CultureInfo.CurrentCulture.EnglishName;
字符串国家=文化.Substring(文化.IndexOf('(')

+ 1,culture.LastIndexOf(')') -culture.IndexOf('(')-

C# 中的客户端国家/地区


获取客户端计算机名称,
如何从服务器获取客户端计算机名称

您将获得以下内容的大部分详细信息
客户端机器使用
“请求.ServerVariables”

// 尝试以下 C# 代码 
System.Net.IPHostEntry 主机 = new System.Net.IPHostEntry(); 
主机 = System.Net.Dns.GetHostByAddress(Request.ServerVariables["REMOTE_HOST"]);

lbl.Text = 主机.主机名;
using System.Globalization;

string culture = CultureInfo.CurrentCulture.EnglishName;
string country = culture.Substring(culture.IndexOf('(')

+ 1, culture.LastIndexOf(')') - culture.IndexOf('(')-

Client Country in C#


Get Client Computer Name,
How to get the client machine name from a server

You will get most of the details of
the client machine using the
"Request.ServerVariables"

// Try the following C# code 
System.Net.IPHostEntry host = new System.Net.IPHostEntry(); 
host = System.Net.Dns.GetHostByAddress(Request.ServerVariables["REMOTE_HOST"]);

lbl.Text = host.HostName;

获取客户端机器ID

半城柳色半声笛 2024-11-18 08:06:58

这些窗口属于其他进程,因此您必须通过窗口系统。这对于每个平台来说都是不同的,并且 AFAIK 没有被 GDK 抽象。

在 X11 上,您可以使用 python 绑定到 libwnck

import wnck
screen = wnck.screen_get_default()
for window in reversed(screen.get_windows_stacked()):
    if window.get_geometry() <matches your click coordinates>

Those windows belong to other processes, so you have to go through the windowing system. This is different for each platform, and AFAIK not abstracted by GDK.

On X11 you could use the python bindings to libwnck:

import wnck
screen = wnck.screen_get_default()
for window in reversed(screen.get_windows_stacked()):
    if window.get_geometry() <matches your click coordinates>

如何使用 Python 和 PyGTK/PyGDK 获取某个 X、Y 位置的窗口?

半城柳色半声笛 2024-11-17 11:36:34

您需要使用以下方式编译它:

g++ inputfile.cpp -o outputbinary

您引用的文件缺少 #include 指令,如果您也将其包含在文件中,则一切都会正常编译。

You'll need to compile it using:

g++ inputfile.cpp -o outputbinary

The file you are referring has a missing #include <cstdlib> directive, if you also include that in your file, everything shall compile fine.

如何在 Linux 上编译 .cpp 文件?

半城柳色半声笛 2024-11-17 08:41:54

也许尝试这样的事情:

var quoteElement = document.getElementById('2');
var quote = quoteElement.value;

// or even ..
var quote = document.getElementById('2').value;

您现在可以在变量中拥有元素的文本值。

Maybe try something like this:

var quoteElement = document.getElementById('2');
var quote = quoteElement.value;

// or even ..
var quote = document.getElementById('2').value;

You would now have the text value of your element in a variable.

将整个代码存储在变量中——Javascript

半城柳色半声笛 2024-11-17 06:22:03

这是我的解决方案,经过一番努力,以小尺寸减小评级栏,甚至没有丑陋的填充

 <RatingBar
        android:id="@+id/listitemrating"
        style="@android:attr/ratingBarStyleSmall"
        android:layout_width="wrap_content"
        android:layout_height="wrap_content"
        android:scaleX=".5"
        android:scaleY=".5"
        android:transformPivotX="0dp"
        android:transformPivotY="0dp"
        android:isIndicator="true"
        android:max="5" />

This was my solution after a lot of struggling to reduce the rating bar in small size without even ugly padding

 <RatingBar
        android:id="@+id/listitemrating"
        style="@android:attr/ratingBarStyleSmall"
        android:layout_width="wrap_content"
        android:layout_height="wrap_content"
        android:scaleX=".5"
        android:scaleY=".5"
        android:transformPivotX="0dp"
        android:transformPivotY="0dp"
        android:isIndicator="true"
        android:max="5" />

如何减小评级栏的大小?

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