How does CMS Create Dynamic Pages

Content Management System (CMS) gives you an easier way to manage sites. It
gives you a nice front-end to write, publish and manage content while hiding
the technical details like FTP, HTML and other coding work. Most of the CMSs
have a web based front-end that means you can manage the whole site from within
the browser. Some examples of popular CMS are Joomla, Wordpress etc.

One major characteristic of CMS is the fact that it creates the whole site
dynamically, it means most (if not all) of the pages that the site has, are
created dynamically. Conventional way of creating site was to create different
HTML pages for each article (page) the site has. Contrary to that most CMS don’t
create different files for pages. They store the content in the Database and
create the pages from the Database. That means the content don’t reside
in pages or files but rather in the Database.

In this post we’re going to create a simple system that will help you
understand how pages are created from the content of the Database this way.
Please note that we’ll not create an example of CMS but just a part of
it.

Database in simple terms is something that is used for storing and retrieving
data. Since we haven’t discussed it yet we’ll not be using it rather
we’ll be using arrays. While arrays and databases have very things in
common, they both can store data, the only feature of the database we need for
this example.

Have a look at the following code:


  <?php
  //these arrays contain title of the articles
  $content_title[0]="Hello world";
  $content_title[1]="How does it look";
  $content_title[2]="PHP is great";
  $content_title[3]="Content Management System";
  $content_title[4]="CMS work this way!";

  //these contain the actual content
  $content_main[0]="First article of this site. 
    blah blah.";
  $content_main[1]="It looks great. blah blah.";
  $content_main[2]="Yeah sure PHP is very useful.
     blah blah.";
  $content_main[3]="Yeah CMS is good and very useful
     for managing sites without much technical knowledge.";
  $content_main[4]="Yeah, it teaches you how a single 
    script can be used to create multi-page site.";

  //the function count returns the number 
  //of elements (strings) in the array (5 in this case)
  $num_pages=count($content_title);

  //catch the data being passed
  $page=$_GET['p'];

  //isset function returns true if the 
  //variable has been assigned a value
  if(!isset($page)) //if page is requested without any GET data
  {//show the homepage
    echo "<h1>My Site: Homepage</h1>";
    echo "Welcome to my Web site. Below are the 
      links to pages to this site:</p>";
    echo "<p><b>LINKS</b></p>";

    //show the links to all the pages with
    //title of contant as anchor text
    //< br /> is used to break line or goto next line.
    for($i=0;$i<$num_pages;$i++)
    {
      echo "<a href=\"cms.php?p=".$i."\">".
        $content_title[$i]."</a> <br />";
    }
  }
  else//if any page is requested
  {
    echo "<h1>My Site</h1>";
    //show title of article 
    echo "<h2>".$content_title[$page]."</h2>";
    //show the main content
    echo "<p>".$content_main[$page]."</p>";
    echo "<p><b>LINKS</b></p>";

    //put the links
    for($i=0;$i<$num_pages;$i++)
    {
      echo "<a href=\"cms.php?p=".$i."\">".
        $content_title[$i]."</a> <br />";
    }
  }
  ?>