include，include_once，require或require_once？ [英] include, include_once, require or require_once?

问题描述

我有PHP文件，我已经定义了服务器访问变量以及 mysql_connect 和 mysql_select_db ，如这个函数经常在后端的每个页面中使用，而我正在使用 include（）这对我现在非常有效，你会建议哪种方法或功能，我会如果我使用 include（）或者使用它是否安全，我想知道是否有任何缺陷？

I have PHP file where I have defined the server access variables as well as the mysql_connect and mysql_select_db, as this functions are regularly used in almost every page in backend, while I am using include() which is perfectly working for me now, which method or function would you suggest and I would like to know if there is any flaw if I use include() or is it safe to use it?

编辑：请记住，我也将使用 $ _ SESSION 变量。

Edit : Keeping in mind I'll be using $_SESSION variable too.

推荐答案

两者之间的唯一区别是需要及其姐妹 require_once 如果找不到文件则抛出致命错误，而包括和 include_once 仅显示警告并继续加载页面的其余部分。如果您不希望PHP在没有数据库信息的情况下尝试加载页面的其余部分（我假设），则使用 require_once 。您不需要多次包含该文件，因此无需使用常规的 require 函数。

The only difference between the two is that require and its sister require_once throw a fatal error if the file is not found, whereas include and include_once only show a warning and continue to load the rest of the page. If you don't want PHP to attempt to load the rest of your page without the database info (which I would assume), then use require_once. You don't need to include the file more than once, so there is no need to use the regular require function.

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