title: UPDATE database and update where variable
body: <p>I have a question in regards to the GET function. I currently have a form with a get action. I am accessing that data in another page with the get function. Unfortunately, I have been getting an "error: undefined index" on every one of my values. After reading up on similar problems, I tried using isset (as seen below) and it gets rid of the error, but I am not sure that my data is stored in the variables at all because if I echo the 4 variables, nothing shows up. Could someone give me a push in the right direction?</p>
  
  <p>Data from form:</p>
  
  <pre><code>while($row = mysql_fetch_array($result)) {
  echo "&lt;div class=\"addform\"&gt;&lt;form method='GET' action=\"update.php\"&gt;\n";
  
  echo "  &lt;input type=\"text\" value=\"".$row['tfid']."\" name=\"tfid\"&gt;\n";
  
  echo "  &lt;input type=\"text\" name=\"fname\"      value=\"".$row['fname']."\"/&gt;\n";
  
  echo "  &lt;input type=\"text\" name=\"lname\" value=\"".$row['lname']."\"/&gt;\n";
  
  echo "  &lt;input type=\"text\" name=\"hca\" value=\"".$row['hca']."\"/&gt;\n";
  
  echo "  &lt;input type=\"text\" name=\"file\" value=\"".$row['file']."\"/&gt;\n";
  
  echo "  &lt;input type=\"image\" src=\"images/update.png\" alt=\"Update Row\" class=\"update\" title=\"Update Row\"&gt;\n";
  
  echo "&lt;a href=\"delete.php?tfid=".$row['tfid']."\"&gt;&lt;img title='Delete Row' alt=\"Delete\" class='del' src='images/delete.png'/&gt;&lt;/a&gt;&lt;/form&gt;&lt;/div&gt;\n";
  
  }
  
  echo "&lt;/table&gt;&lt;br /&gt;\n";
  </code></pre>
  
  <p>and the code for retrieval:</p>
  
  <pre><code>$tfid= isset($_GET["tfid"]) ? $_GET["tfid"] : NULL;
  $fname = isset($_GET["fname"]) ? $_GET["fname"] : NULL;
  $lname = isset($_GET["lname"]) ? $_GET["lname"] : NULL;
  $hca = isset($_GET["hca"]) ? $_GET["hca"] : NULL;
  echo $tfid;
  echo $fname;
  echo $lname;
  echo $hca;
  </code></pre>