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I want to find all parent ids of a given taxonomy term id recursively, without loading them. Existing taxonomy functions like taxonomy_get_parents_all() and taxonomy_get_parents() are loading the terms.

Since I will be using this result in an API function, it is important for me to get the parents with a minimum performance overhead. All I need to get the parents in a simple array like: $parents = array(6, 3, 2);

1

Have a look at taxonomy_get_parents() and taxonomy_get_parents_all().

You could copy most of the functions but skip

$parents[$tid] = taxonomy_term_load_multiple($tids);

to not load the terms.

/**
 * Load a terms parent.
 */
function MODULE_taxonomy_get_parents($tid) {
  $parents = &drupal_static(__FUNCTION__, array());

  if ($tid && !isset($parents[$tid])) {
    $query = db_select('taxonomy_term_data', 't');
    $query->join('taxonomy_term_hierarchy', 'h', 'h.parent = t.tid');
    $query->addField('t', 'tid');
    $query->condition('h.tid', $tid);
    $query->addTag('term_access');
    $query->orderBy('t.weight');
    $query->orderBy('t.name');
    // $tids = $query->execute()->fetchCol();
    // $parents[$tid] = taxonomy_term_load_multiple($tids);
    $tids = $query->execute()->fetchAll();
    $parents[$tid] =  $tids;
  }

  return isset($parents[$tid]) ? $parents[$tid] : array();    
}

/**
 * Load all parents for a term.
 */
function MODULE_taxonomy_get_parents_all($tid) {
  $cache = &drupal_static(__FUNCTION__, array());

  if (isset($cache[$tid])) {
    return $cache[$tid];
  }

  $parents = array();
  if ($term = taxonomy_term_load($tid)) {
    $parents[] = $term;
    $n = 0;
    // while ($parent = taxonomy_get_parents($parents[$n]->tid)) {
    while ($parent = MODULE_taxonomy_get_parents($parents[$n]->tid)) {
      $parents = array_merge($parents, $parent);
      $n++;
    }
  }

  $cache[$tid] = $parents;

  return $parents;
}

If you don't need any access control or sorting you can just query the taxonomy_term_hierarchy table directly.

$query = db_select('taxonomy_term_hierarchy', 'h');
$query->addField('h', 'parent', tid);
$query->condition('tid', $tid);
$query->condition('parent', 0, '!=');
$tids = $query->execute()->fetchAll();
$parents[$tid] =  $tids;
  • This returns only the first parent of a given term, not the parents of the parents recursively. – Елин Й. Jan 25 '16 at 17:33
  • @ЕлинЙ. I updated the answer so that it returns all parents. – Marcus Aschan Jan 26 '16 at 9:29
  • Thank you Marcus for your answer. Although it is a valid solution for my question, it is not an effective solution that I'm seeking. It recursively makes a database query for each parent term (which Drupal core is also doing that way). I had already done it in a similar but with a simpler query. I hoped for a solution which makes it with an only one query at all. – Елин Й. Jan 27 '16 at 17:15
0

I managed to achieve that as follows:

function MYMODULE_taxonomy_get_parents($tid) {
  $taxonomy_hierarchy = db_query('SELECT tid, parent FROM {taxonomy_term_hierarchy} 
                                  WHERE parent != 0')
                        ->fetchAllKeyed();
  $parent_tids = array();

  while (!empty($taxonomy_hierarchy[$tid])) {
    $tid = $taxonomy_hierarchy[$tid];
    $parent_tids[] = $tid;
  }

  return $parent_tids;
}

I have also added some static caching, but for the brevity I didn't include it in this answer.

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