Add term tree into a taxonomy

add_terms.php

<?php

// Structure to use
$terms = array(
  array('name' => 'Technical', 'weight' => 1, 'parent' => 0),
  array('name' => 'Operations', 'weight' => 6, 'parent' => 0),
  array('name' => 'Customer Relationship', 'weight' => 7, 'parent' => 0),
  array('name' => 'Talent & Culture', 'weight' => 11, 'parent' => 0),
  array('name' => 'Finance', 'weight' => 12, 'parent' => 0),
  array('name' => 'Dev', 'weight' => 0, 'parent' => 'Technical'),
  array('name' => 'QA', 'weight' => 1, 'parent' => 'Technical'),
  array('name' => 'PM', 'weight' => 2, 'parent' => 'Technical'),
  array('name' => 'BA', 'weight' => 3, 'parent' => 'Technical'),
  array('name' => 'FE', 'weight' => 4, 'parent' => 'Technical'),
  array('name' => 'Sales', 'weight' => 0, 'parent' => 'Customer Relationship'),
  array('name' => 'BD', 'weight' => 1, 'parent' => 'Customer Relationship'),
  array('name' => 'Marketing', 'weight' => 2, 'parent' => 'Customer Relationship'),
);

_add_taxonomy_tree($terms);
exit(0)

/**
 * Add terms to $vocabulary given in array $terms.
 *
 * The $terms array has one or more arrayss with the following structure:
 *
 *   array(
 *     array( 
 *       'name' => 'Term name',
 *       'weight' => 1,
 *       'parent' => '0 or the name of the parent term'
 *     ),
 *     ...
 *   );
 *
 * @param $vacabulary_name    Machine name of vocabulary
 * @param $terms              Term array structure.
 */
function _add_taxonomy_tree($vocabulary_name, $terms) {

  // Create taxonomy terms. It assumes just one parent per term
  $voc = taxonomy_vocabulary_machine_name_load($vocabulary_name);
  $vid = $voc->vid;
  $all_terms = array();
  $tree = taxonomy_get_tree($vid);
  foreach($tree as $tree_item) {
    $all_terms[$tree_item->name] = $tree_item->tid;
  }
  foreach ($terms as $term) {
    $term['vid'] = $vid;
    if ($term['parent'] !== 0) {
      $parent_name = $term['parent'];
      if (isset($all_terms[$parent_name])) {
        $term['parent'] = array($all_terms[$parent_name]);
      }
    }
    $term = (object) $term;
    taxonomy_term_save($term);
    $all_terms[$term->name] = $term->tid;
  }
}