PHP include file path problem

I have just been learning PHP recently, and I am working on a small project. I use a lot of require and include, and I am confused by absolute paths and relative paths. I finally figured it out.

1. The relative path of php is based on the running script. For example, A contains B and B contains C. If A and C are in the same directory, the path containing C in B should be relative to A. If B , C are in the same level directory, then the path containing C in B is relative to C.

2. No matter how the .php script is included, dirname(__FILE__) gets the absolute path of the folder where the script is located.

It is difficult to apply these two rules accurately, at least I often get confused myself, so I used a trickier method and wrote a path.php myself, so that I rarely make mistakes.

 <?php
      define(&#39;ROOT_PATH&#39;,dirname(__FILE__));
      define(&#39;ACTION_PATH&#39;,ROOT_PATH.&#39;/action/&#39;);
      define(&#39;BEAN_PATH&#39;,ROOT_PATH.&#39;/bean/&#39;);
      define(&#39;DAO_PATH&#39;,ROOT_PATH.&#39;/dao/&#39;);
      define(&#39;IPADVIEW_PATH&#39;,ROOT_PATH.&#39;/ipadView/&#39;);
      define(&#39;VIEW_PATH&#39;,ROOT_PATH.&#39;/view/&#39;);
    ?>