How to Check if a CCK Field Exists on a Node

There are times it's important to check to see if a CCK field exists, or has a value, on a node before trying to do sometihng with it. 

Here's an example I used in node--blog.tpl.php to now show the thumbail if the Show Thumbnail custom field is set to No.  The reason I had to do this was because I added this field after LOTS of nodes had already been created.  I was getting 'index not defined' error messages on my old content because those nodes did not have a value for that field since the field didn't exist when the node was originally created.

<?php

                                  $showthumb = "Yes";  //set default to Yes
                               
                                  $my_field_items = field_get_items('node', $node, 'field_show_thumb_on_post');
                                  if ($my_field_items) {
                                    $my_field_first_item = reset($my_field_items);
                                    $my_field_value = $my_field_first_item['value'];
                                    $showthumb = $my_field_value;  //set it to whatever the node has it set to since we know this particular node has a value for the field
                                  }
                               
                                  if ($showthumb == "Yes"){
                                      print render($content['field_blog_image']) ;
                                  }

?>

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