EntityFieldQuery is a class, new to Drupal 7, that allows retrieval of a set of entities based on specified conditions. It allows finding of entities based on entity properties, field values, and other generic entity metadata. The syntax is really compact and easy to follow, as well. And, best of all, it's core Drupal; no additional modules are …

Exemple EntityFieldQuery

<?php
$query = new EntityFieldQuery();

$query->entityCondition('entity_type', 'node')
  ->entityCondition('bundle', 'article')
  ->propertyCondition('status', 1)
  ->fieldCondition('field_news_types', 'value', 'spotlight', '=')
  ->fieldCondition('field_photo', 'fid', 'NULL', '!=')
  ->fieldCondition('field_faculty_tag', 'tid', $value)
  ->fieldCondition('field_news_publishdate', 'value', $year. '%', 'like')
  ->fieldOrderBy('field_photo', 'fid', 'DESC')
  ->range(0, 10)
  ->addMetaData('account', user_load(1)); // Run the query as user 1.

$result = $query->execute();

if (isset($result['node'])) {
  $news_items_nids = array_keys($result['node']);
  $news_items = entity_load('node', $news_items_nids);
}
?>