update node field without node be updated I want to update a field of node programmically,I did it with below code

$node = node_load($nid);
        $node-&gt;field_share_counter['und'][0]['value'] = intval($node-&gt;field_share_counter['und'][0]['value']) + 1;
        node_save($node);


but after update with this method the node will be update,I mean in content show that this node recently update, I want update custom field without the node updated.also I know db_update is suitable for update a field of table in db but in here I dont know how achieve this job.

tnx
I found this http://timonweb.com/how-insert-and-update-only-specific-fields-your-entity-drupal-7 and it is useful and final solution is :

$node-&gt;field_share_counter['und'][0]['value'] = intval($node-&gt;field_share_counter['und'][0]['value']) + 1;
        //$node-&gt;field_product_description[$node-&gt;language][0]['value'] = 'This is a very nice and useful product. Buy it now! We want your money!';

            // Get the numeric id of your field by passing field name
            $info = field_info_field('field_share_counter');
            $fields = array($info['id']);

            // Execute the storage function
            field_sql_storage_field_storage_write('node', $node, 'update', $fields);

            // Clear field cache
            cache_clear_all("field:node:$node-&gt;nid", 'cache_field');