plugins/views_plugin_query_default.inc

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<?php
class views_plugin_query_default extends views_plugin_query {

  var $table_queue = array();

  var $tables = array();

  var $relationships = array();

  var $where = array();
  var $having = array();
  var $group_operator = 'AND';

  var $orderby = array();

  var $groupby = array();

  var $header = array();

  var $distinct = FALSE;

  var $has_aggregate = FALSE;

  var $get_count_optimized = NULL;

   var $pager = NULL;

   var $field_aliases = array();

   var $tags = array();

  function init($base_table = 'node', $base_field = 'nid', $options) {
    parent::init($base_table, $base_field, $options);
    $this->base_table = $base_table;  // Predefine these above, for clarity.
    $this->base_field = $base_field;
    $this->relationships[$base_table] = array(
      'link' => NULL,
      'table' => $base_table,
      'alias' => $base_table,
      'base' => $base_table
    );

    // init the table queue with our primary table.
    $this->table_queue[$base_table] = array(
      'alias' => $base_table,
      'table' => $base_table,
      'relationship' => $base_table,
      'join' => NULL,
    );

    // init the tables with our primary table
    $this->tables[$base_table][$base_table] = array(
      'count' => 1,
      'alias' => $base_table,
    );

    $this->count_field = array(
      'table' => $base_table,
      'field' => $base_field,
      'alias' => $base_field,
      'count' => TRUE,
    );
  }

  // ----------------------------------------------------------------
  // Utility methods to set flags and data.

  function set_distinct($value = TRUE) {
    if (!(isset($this->no_distinct) && $value)) {
      $this->distinct = $value;
    }
  }

  function set_count_field($table, $field, $alias = NULL) {
    if (empty($alias)) {
      $alias = $table . '_' . $field;
    }
    $this->count_field = array(
      'table' => $table,
      'field' => $field,
      'alias' => $alias,
      'count' => TRUE,
    );
  }

  function set_header($header) {
    $this->header = $header;
  }

  function option_definition() {
    $options = parent::option_definition();
    $options['disable_sql_rewrite'] = array(
      'default' => FALSE,
      'translatable' => FALSE,
      'bool' => TRUE,
    );
    $options['distinct'] = array(
      'default' => FALSE,
      'bool' => TRUE,
    );
    $options['slave'] = array(
      'default' => FALSE,
      'bool' => TRUE,
    );
    $options['query_comment'] = array(
      'default' => '',
      'bool' => FALSE,
    );

    return $options;
  }

  function options_form(&$form, &$form_state) {
    parent::options_form($form, $form_state);

    $form['disable_sql_rewrite'] = array(
      '#title' => t('Disable SQL rewriting'),
      '#description' => t('Disabling SQL rewriting will disable node_access checks as well as other modules that implement hook_query_alter().'),
      '#type' => 'checkbox',
      '#default_value' => !empty($this->options['disable_sql_rewrite']),
      '#suffix' => '<div class="messages warning sql-rewrite-warning js-hide">' . t('WARNING: Disabling SQL rewriting means that node access security is disabled. This may allow users to see data they should not be able to see if your view is misconfigured. Please use this option only if you understand and accept this security risk.') . '</div>',
    );
    $form['distinct'] = array(
      '#type' => 'checkbox',
      '#title' => t('Distinct'),
      '#description' => t('This will make the view display only distinct items. If there are multiple identical items, each will be displayed only once. You can use this to try and remove duplicates from a view, though it does not always work. Note that this can slow queries down, so use it with caution.'),
      '#default_value' => !empty($this->options['distinct']),
    );
    $form['slave'] = array(
      '#type' => 'checkbox',
      '#title' => t('Use Slave Server'),
      '#description' => t('This will make the query attempt to connect to a slave server if available.  If no slave server is defined or available, it will fall back to the default server.'),
      '#default_value' => !empty($this->options['slave']),
    );
    $form['query_comment'] = array(
      '#type' => 'textfield',
      '#title' => t('Query Comment'),
      '#description' => t('If set, this comment will be embedded in the query and passed to the SQL server. This can be helpful for logging or debugging.'),
      '#default_value' => $this->options['query_comment'],
    );
  }

  // ----------------------------------------------------------------
  // Table/join adding

  function add_relationship($alias, $join, $base, $link_point = NULL) {
    if (empty($link_point)) {
      $link_point = $this->base_table;
    }
    elseif (!array_key_exists($link_point, $this->relationships)) {
      return FALSE;
    }

    // Make sure $alias isn't already used; if it, start adding stuff.
    $alias_base = $alias;
    $count = 1;
    while (!empty($this->relationships[$alias])) {
      $alias = $alias_base . '_' . $count++;
    }

    // Make sure this join is adjusted for our relationship.
    if ($link_point && isset($this->relationships[$link_point])) {
      $join = $this->adjust_join($join, $link_point);
    }

    // Add the table directly to the queue to avoid accidentally marking
    // it.
    $this->table_queue[$alias] = array(
      'table' => $join->table,
      'num' => 1,
      'alias' => $alias,
      'join' => $join,
      'relationship' => $link_point,
    );

    $this->relationships[$alias] = array(
      'link' => $link_point,
      'table' => $join->table,
      'base' => $base,
    );

    $this->tables[$this->base_table][$alias] = array(
      'count' => 1,
      'alias' => $alias,
    );

    return $alias;
  }

  function add_table($table, $relationship = NULL, $join = NULL, $alias = NULL) {
    if (!$this->ensure_path($table, $relationship, $join)) {
      return FALSE;
    }

    if ($join && $relationship) {
      $join = $this->adjust_join($join, $relationship);
    }

    return $this->queue_table($table, $relationship, $join, $alias);
  }

  function queue_table($table, $relationship = NULL, $join = NULL, $alias = NULL) {
    // If the alias is set, make sure it doesn't already exist.
    if (isset($this->table_queue[$alias])) {
      return $alias;
    }

    if (empty($relationship)) {
      $relationship = $this->base_table;
    }

    if (!array_key_exists($relationship, $this->relationships)) {
      return FALSE;
    }

    if (!$alias && $join && $relationship && !empty($join->adjusted) && $table != $join->table) {
      if ($relationship == $this->base_table) {
        $alias = $table;
      }
      else {
        $alias = $relationship . '_' . $table;
      }
    }

    // Check this again to make sure we don't blow up existing aliases for already
    // adjusted joins.
    if (isset($this->table_queue[$alias])) {
      return $alias;
    }

    $alias = $this->mark_table($table, $relationship, $alias);

    // If no alias is specified, give it the default.
    if (!isset($alias)) {
      $alias = $this->tables[$relationship][$table]['alias'] . $this->tables[$relationship][$table]['count'];
    }

    // If this is a relationship based table, add a marker with
    // the relationship as a primary table for the alias.
    if ($table != $alias) {
      $this->mark_table($alias, $this->base_table, $alias);
    }

    // If no join is specified, pull it from the table data.
    if (!isset($join)) {
      $join = $this->get_join_data($table, $this->relationships[$relationship]['base']);
      if (empty($join)) {
        return FALSE;
      }

      $join = $this->adjust_join($join, $relationship);
    }

    $this->table_queue[$alias] = array(
      'table' => $table,
      'num' => $this->tables[$relationship][$table]['count'],
      'alias' => $alias,
      'join' => $join,
      'relationship' => $relationship,
    );

    return $alias;
  }

  function mark_table($table, $relationship, $alias) {
    // Mark that this table has been added.
    if (empty($this->tables[$relationship][$table])) {
      if (!isset($alias)) {
        $alias = '';
        if ($relationship != $this->base_table) {
          // double underscore will help prevent accidental name
          // space collisions.
          $alias = $relationship . '__';
        }
        $alias .= $table;
      }
      $this->tables[$relationship][$table] = array(
        'count' => 1,
        'alias' => $alias,
      );
    }
    else {
      $this->tables[$relationship][$table]['count']++;
    }

    return $alias;
  }

  function ensure_table($table, $relationship = NULL, $join = NULL) {
    // ensure a relationship
    if (empty($relationship)) {
      $relationship = $this->base_table;
    }

    // If the relationship is the primary table, this actually be a relationship
    // link back from an alias. We store all aliases along with the primary table
    // to detect this state, because eventually it'll hit a table we already
    // have and that's when we want to stop.
    if ($relationship == $this->base_table && !empty($this->tables[$relationship][$table])) {
      return $this->tables[$relationship][$table]['alias'];
    }

    if (!array_key_exists($relationship, $this->relationships)) {
      return FALSE;
    }

    if ($table == $this->relationships[$relationship]['base']) {
      return $relationship;
    }

    // If we do not have join info, fetch it.
    if (!isset($join)) {
      $join = $this->get_join_data($table, $this->relationships[$relationship]['base']);
    }

    // If it can't be fetched, this won't work.
    if (empty($join)) {
      return;
    }

    // Adjust this join for the relationship, which will ensure that the 'base'
    // table it links to is correct. Tables adjoined to a relationship
    // join to a link point, not the base table.
    $join = $this->adjust_join($join, $relationship);

    if ($this->ensure_path($table, $relationship, $join)) {
      // Attempt to eliminate redundant joins.  If this table's
      // relationship and join exactly matches an existing table's
      // relationship and join, we do not have to join to it again;
      // just return the existing table's alias.  See
      // http://groups.drupal.org/node/11288 for details.
      //
      // This can be done safely here but not lower down in
      // queue_table(), because queue_table() is also used by
      // add_table() which requires the ability to intentionally add
      // the same table with the same join multiple times.  For
      // example, a view that filters on 3 taxonomy terms using AND
      // needs to join taxonomy_term_data 3 times with the same join.

      // scan through the table queue to see if a matching join and
      // relationship exists.  If so, use it instead of this join.

      // TODO: Scanning through $this->table_queue results in an
      // O(N^2) algorithm, and this code runs every time the view is
      // instantiated (Views 2 does not currently cache queries).
      // There are a couple possible "improvements" but we should do
      // some performance testing before picking one.
      foreach ($this->table_queue as $queued_table) {
        // In PHP 4 and 5, the == operation returns TRUE for two objects
        // if they are instances of the same class and have the same
        // attributes and values.
        if ($queued_table['relationship'] == $relationship && $queued_table['join'] == $join) {
          return $queued_table['alias'];
        }
      }

      return $this->queue_table($table, $relationship, $join);
    }
  }

  function ensure_path($table, $relationship = NULL, $join = NULL, $traced = array(), $add = array()) {
    if (!isset($relationship)) {
      $relationship = $this->base_table;
    }

    if (!array_key_exists($relationship, $this->relationships)) {
      return FALSE;
    }

    // If we do not have join info, fetch it.
    if (!isset($join)) {
      $join = $this->get_join_data($table, $this->relationships[$relationship]['base']);
    }

    // If it can't be fetched, this won't work.
    if (empty($join)) {
      return FALSE;
    }

    // Does a table along this path exist?
    if (isset($this->tables[$relationship][$table]) ||
      ($join && $join->left_table == $relationship) ||
      ($join && $join->left_table == $this->relationships[$relationship]['table'])) {

      // Make sure that we're linking to the correct table for our relationship.
      foreach (array_reverse($add) as $table => $path_join) {
        $this->queue_table($table, $relationship, $this->adjust_join($path_join, $relationship));
      }
      return TRUE;
    }

    // Have we been this way?
    if (isset($traced[$join->left_table])) {
      // we looped. Broked.
      return FALSE;
    }

    // Do we have to add this table?
    $left_join = $this->get_join_data($join->left_table, $this->relationships[$relationship]['base']);
    if (!isset($this->tables[$relationship][$join->left_table])) {
      $add[$join->left_table] = $left_join;
    }

    // Keep looking.
    $traced[$join->left_table] = TRUE;
    return $this->ensure_path($join->left_table, $relationship, $left_join, $traced, $add);
  }

  function adjust_join($join, $relationship) {
    if (!empty($join->adjusted)) {
      return $join;
    }

    if (empty($relationship) || empty($this->relationships[$relationship])) {
      return $join;
    }

    // Adjusts the left table for our relationship.
    if ($relationship != $this->base_table) {
      // If we're linking to the primary table, the relationship to use will
      // be the prior relationship. Unless it's a direct link.

      // Safety! Don't modify an original here.
      $join = clone $join;

      // Do we need to try to ensure a path?
      if ($join->left_table != $this->relationships[$relationship]['table'] &&
          $join->left_table != $this->relationships[$relationship]['base'] &&
          !isset($this->tables[$relationship][$join->left_table]['alias'])) {
        $this->ensure_table($join->left_table, $relationship);
      }

      // First, if this is our link point/anchor table, just use the relationship
      if ($join->left_table == $this->relationships[$relationship]['table']) {
        $join->left_table = $relationship;
      }
      // then, try the base alias.
      elseif (isset($this->tables[$relationship][$join->left_table]['alias'])) {
        $join->left_table = $this->tables[$relationship][$join->left_table]['alias'];
      }
      // But if we're already looking at an alias, use that instead.
      elseif (isset($this->table_queue[$relationship]['alias'])) {
        $join->left_table = $this->table_queue[$relationship]['alias'];
      }
    }

    $join->adjusted = TRUE;
    return $join;
  }

  function get_join_data($table, $base_table) {
    // Check to see if we're linking to a known alias. If so, get the real
    // table's data instead.
    if (!empty($this->table_queue[$table])) {
      $table = $this->table_queue[$table]['table'];
    }
    return views_get_table_join($table, $base_table);
  }

  function get_table_info($table) {
    if (!empty($this->table_queue[$table])) {
      return $this->table_queue[$table];
    }

    // In rare cases we might *only* have aliased versions of the table.
    if (!empty($this->tables[$this->base_table][$table])) {
      $alias = $this->tables[$this->base_table][$table]['alias'];
      if (!empty($this->table_queue[$alias])) {
        return $this->table_queue[$alias];
      }
    }
  }

  function add_field($table, $field, $alias = '', $params = array()) {
    // We check for this specifically because it gets a special alias.
    if ($table == $this->base_table && $field == $this->base_field && empty($alias)) {
      $alias = $this->base_field;
    }

    if ($table && empty($this->table_queue[$table])) {
      $this->ensure_table($table);
    }

    if (!$alias && $table) {
      $alias = $table . '_' . $field;
    }

    // Make sure an alias is assigned
    $alias = $alias ? $alias : $field;

    // PostgreSQL truncates aliases to 63 characters: http://drupal.org/node/571548

    // We limit the length of the original alias up to 60 characters
    // to get a unique alias later if its have duplicates
    $alias = strtolower(substr($alias, 0, 60));

    // Create a field info array.
    $field_info = array(
      'field' => $field,
      'table' => $table,
      'alias' => $alias,
    ) + $params;

    // Test to see if the field is actually the same or not. Due to
    // differing parameters changing the aggregation function, we need
    // to do some automatic alias collision detection:
    $base = $alias;
    $counter = 0;
    while (!empty($this->fields[$alias]) && $this->fields[$alias] != $field_info) {
      $field_info['alias'] = $alias = $base . '_' . ++$counter;
    }

    if (empty($this->fields[$alias])) {
      $this->fields[$alias] = $field_info;
    }

    // Keep track of all aliases used.
    $this->field_aliases[$table][$field] = $alias;

    return $alias;
  }

  function clear_fields() {
    $this->fields = array();
  }

  function add_where($group, $field, $value = NULL, $operator = NULL) {
    // Ensure all variants of 0 are actually 0. Thus '', 0 and NULL are all
    // the default group.
    if (empty($group)) {
      $group = 0;
    }

    // Check for a group.
    if (!isset($this->where[$group])) {
      $this->set_where_group('AND', $group);
    }

    $this->where[$group]['conditions'][] = array(
      'field' => $field,
      'value' => $value,
      'operator' => $operator,
    );
  }

  function add_where_expression($group, $snippet, $args = array()) {
    // Ensure all variants of 0 are actually 0. Thus '', 0 and NULL are all
    // the default group.
    if (empty($group)) {
      $group = 0;
    }

    // Check for a group.
    if (!isset($this->where[$group])) {
      $this->set_where_group('AND', $group);
    }

    $this->where[$group]['conditions'][] = array(
      'field' => $snippet,
      'value' => $args,
      'operator' => 'formula',
    );
  }

  function add_having($group, $field, $value = NULL, $operator = NULL) {
    // Ensure all variants of 0 are actually 0. Thus '', 0 and NULL are all
    // the default group.
    if (empty($group)) {
      $group = 0;
    }

    // Check for a group.
    if (!isset($this->having[$group])) {
      $this->set_where_group('AND', $group, 'having');
    }

    // Add the clause and the args.
    $this->having[$group]['conditions'][] = array(
      'field' => $field,
      'value' => $value,
      'operator' => $operator,
    );
  }

  function add_having_expression($group, $snippet, $args = array()) {
    // Ensure all variants of 0 are actually 0. Thus '', 0 and NULL are all
    // the default group.
    if (empty($group)) {
      $group = 0;
    }

    // Check for a group.
    if (!isset($this->having[$group])) {
      $this->set_where_group('AND', $group, 'having');
    }

    // Add the clause and the args.
    $this->having[$group]['conditions'][] = array(
      'field' => $snippet,
      'value' => $args,
      'operator' => 'formula',
    );
  }

  function add_orderby($table, $field = NULL, $order = 'ASC', $alias = '', $params = array()) {
    // Only ensure the table if it's not the special random key.
    // @todo: Maybe it would make sense to just add a add_orderby_rand or something similar.
    if ($table && $table != 'rand') {
      $this->ensure_table($table);
    }

    // Only fill out this aliasing if there is a table;
    // otherwise we assume it is a formula.
    if (!$alias && $table) {
      $as = $table . '_' . $field;
    }
    else {
      $as = $alias;
    }

    if ($field) {
      $as = $this->add_field($table, $field, $as, $params);
    }

    $this->orderby[] = array(
      'field' => $as,
      'direction' => strtoupper($order)
    );

  }

  function add_groupby($clause) {
    // Only add it if it's not already in there.
    if (!in_array($clause, $this->groupby)) {
      $this->groupby[] = $clause;
    }
  }

  function get_field_alias($table_alias, $field) {
    return isset($this->field_aliases[$table_alias][$field]) ? $this->field_aliases[$table_alias][$field] : FALSE;
  }

  function add_tag($tag) {
    $this->tags[] = $tag;
  }

  function placeholder($base = 'views') {
    static $placeholders = array();
    if (!isset($placeholders[$base])) {
      $placeholders[$base] = 0;
      return ':' . $base;
    }
    else {
      return ':' . $base . ++$placeholders[$base];
    }
  }

  function build_condition($where = 'where') {
    $has_condition = FALSE;
    $has_arguments = FALSE;
    $has_filter = FALSE;

    $main_group = db_and();
    $filter_group = $this->group_operator == 'OR' ? db_or() : db_and();

    foreach ($this->$where as $group => $info) {

      if (!empty($info['conditions'])) {
        $sub_group = $info['type'] == 'OR' ? db_or() : db_and();
        foreach ($info['conditions'] as $key => $clause) {
          // DBTNG doesn't support to add the same subquery twice to the main
          // query and the count query, so clone the subquery to have two instances
          // of the same object. - http://drupal.org/node/1112854
          if (is_object($clause['value']) && $clause['value'] instanceof SelectQuery) {
            $clause['value'] = clone $clause['value'];
          }
          if ($clause['operator'] == 'formula') {
            $has_condition = TRUE;
            $sub_group->where($clause['field'], $clause['value']);
          }
          else {
            $has_condition = TRUE;
            $sub_group->condition($clause['field'], $clause['value'], $clause['operator']);
          }
        }

        // Add the item to the filter group.
        if ($group != 0) {
          $has_filter = TRUE;
          $filter_group->condition($sub_group);
        }
        else {
          $has_arguments = TRUE;
          $main_group->condition($sub_group);
        }
      }
    }

    if ($has_filter) {
      $main_group->condition($filter_group);
    }

    if (!$has_arguments && $has_condition) {
      return $filter_group;
    }
    if ($has_arguments && $has_condition) {
      return $main_group;
    }
  }

  function compile_fields($fields_array, $query) {
    $non_aggregates = array();
    foreach ($fields_array as $field) {
      $string = '';
      if (!empty($field['table'])) {
        $string .= $field['table'] . '.';
      }
      $string .= $field['field'];
      $fieldname = (!empty($field['alias']) ? $field['alias'] : $string);

      if (!empty($field['distinct'])) {
        throw new Exception("Column-level distinct is not supported anymore.");
      }

      if (!empty($field['count'])) {
        // Retained for compatibility
        $field['function'] = 'count';
        // It seems there's no way to abstract the table+column reference
        // without adding a field, aliasing, and then using the alias.
      }

      if (!empty($field['function'])) {
        $info = $this->get_aggregation_info();
        if (!empty($info[$field['function']]['method']) && function_exists($info[$field['function']]['method'])) {
          $string = $info[$field['function']]['method']($field['function'], $string);
          $placeholders = !empty($field['placeholders']) ? $field['placeholders'] : array();
          $query->addExpression($string, $fieldname, $placeholders);
        }

        $this->has_aggregate = TRUE;
      }
      // This is a formula, using no tables.
      elseif (empty($field['table'])) {
        $placeholders = !empty($field['placeholders']) ? $field['placeholders'] : array();
        $query->addExpression($string, $fieldname, $placeholders);
      }

      elseif ($this->distinct && !in_array($fieldname, $this->groupby)) {
        // d7cx: This code was there, apparently needed for PostgreSQL
        // $string = db_driver() == 'pgsql' ? "FIRST($string)" : $string;
        $query->addField(!empty($field['table']) ? $field['table'] : $this->base_table, $field['field'], $fieldname);
      }
      elseif (empty($field['aggregate'])) {
        $non_aggregates[] = $fieldname;
        $query->addField(!empty($field['table']) ? $field['table'] : $this->base_table, $field['field'], $fieldname);
      }

      // @TODO Remove this old code.
      if (!empty($field['distinct']) && empty($field['function'])) {
        $distinct[] = $string;
      }
      else {
        $fields[] = $string;
      }

      if ($this->get_count_optimized) {
        // We only want the first field in this case.
        break;
      }
    }
    return array(
      $non_aggregates,
    );
  }

  function query($get_count = FALSE) {
    // Check query distinct value.
    if (empty($this->no_distinct) && $this->distinct && !empty($this->fields)) {
      $base_field_alias = $this->add_field($this->base_table, $this->base_field);
      $this->add_groupby($base_field_alias);
      $distinct = TRUE;
    }

    $fields_array = $this->fields;
    if ($get_count && !$this->groupby) {
      foreach ($fields_array as $field) {
        if (!empty($field['distinct']) || !empty($field['function'])) {
          $this->get_count_optimized = FALSE;
          break;
        }
      }
    }
    else {
      $this->get_count_optimized = FALSE;
    }
    if (!isset($this->get_count_optimized)) {
      $this->get_count_optimized = TRUE;
    }

    $options = array();
    $target = 'default';
    $key = 'default';
    // Detect an external database and set the
    if (isset($this->view->base_database)) {
      $key = $this->view->base_database;
    }

    // Set the slave target if the slave option is set
    if (!empty($this->options['slave'])) {
      $target = 'slave';
    }

    // Go ahead and build the query.
    // db_select doesn't support to specify the key, so use getConnection directly.
    $query = Database::getConnection($target, $key)
      ->select($this->base_table, $this->base_table, $options)
      ->addTag('views')
      ->addTag('views_' . $this->view->name);

    // Add the tags added to the view itself.
    foreach ($this->tags as $tag) {
      $query->addTag($tag);
    }

    if (!empty($distinct)) {
      $query->distinct();
    }

    $joins = $where = $having = $orderby = $groupby = '';
    $fields = $distinct = array();

    // Add all the tables to the query via joins. We assume all LEFT joins.
    foreach ($this->table_queue as $table) {
      if (is_object($table['join'])) {
        $table['join']->build_join($query, $table, $this);
      }
    }

    $this->has_aggregate = FALSE;
    $non_aggregates = array();

    list($non_aggregates) = $this->compile_fields($fields_array, $query);

    if (count($this->having)) {
      $this->has_aggregate = TRUE;
    }
    if ($this->has_aggregate && (!empty($this->groupby) || !empty($non_aggregates))) {
      $groupby = array_unique(array_merge($this->groupby, $non_aggregates));
      foreach ($groupby as $field) {
        $query->groupBy($field);
      }
      if (!empty($this->having) && $condition = $this->build_condition('having')) {
        $query->havingCondition($condition);
      }
    }

    if (!$this->get_count_optimized) {
      // we only add the orderby if we're not counting.
      if ($this->orderby) {
        foreach ($this->orderby as $order) {
          if ($order['field'] == 'rand_') {
            $query->orderRandom();
          }
          else {
            $query->orderBy($order['field'], $order['direction']);
          }
        }
      }
    }

    if (!empty($this->where) && $condition = $this->build_condition('where')) {
      $query->condition($condition);
    }

    // Add a query comment.
    if (!empty($this->options['query_comment'])) {
      $query->comment($this->options['query_comment']);
    }

    // Add all query substitutions as metadata.
    $query->addMetaData('views_substitutions', module_invoke_all('views_query_substitutions', $this));

    return $query;
  }

  function get_where_args() {
    $args = array();
    foreach ($this->where as $group => $where) {
      $args = array_merge($args, $where['args']);
    }
    foreach ($this->having as $group => $having) {
      $args = array_merge($args, $having['args']);
    }
    return $args;
  }

  function alter(&$view) {
    foreach (module_implements('views_query_alter') as $module) {
      $function = $module . '_views_query_alter';
      $function($view, $this);
    }
  }

  function build(&$view) {
    // Make the query distinct if the option was set.
    if (!empty($this->options['distinct'])) {
      $this->set_distinct();
    }

    // Store the view in the object to be able to use it later.
    $this->view = $view;

    $view->init_pager();

    // Let the pager modify the query to add limits.
    $this->pager->query();

    $view->build_info['query'] = $this->query();
    $view->build_info['count_query'] = $this->query(TRUE);
  }

  function execute(&$view) {
    $external = FALSE; // Whether this query will run against an external database.
    $query = $view->build_info['query'];
    $count_query = $view->build_info['count_query'];

    $query->addMetaData('view', $view);
    $count_query->addMetaData('view', $view);

    if (empty($this->options['disable_sql_rewrite'])) {
      $base_table_data = views_fetch_data($this->base_table);
      if (isset($base_table_data['table']['base']['access query tag'])) {
        $access_tag = $base_table_data['table']['base']['access query tag'];
        $query->addTag($access_tag);
        $count_query->addTag($access_tag);
      }
    }

    $items = array();
    if ($query) {
      $additional_arguments = module_invoke_all('views_query_substitutions', $view);

      // Count queries must be run through the preExecute() method.
      // If not, then hook_query_node_access_alter() may munge the count by
      // adding a distinct against an empty query string
      // (e.g. COUNT DISTINCT(1) ...) and no pager will return.
      // See pager.inc > PagerDefault::execute()
      // http://api.drupal.org/api/drupal/includes--pager.inc/function/PagerDefault::execute/7
      // See http://drupal.org/node/1046170.
      $count_query->preExecute();

      // Build the count query.
      $count_query = $count_query->countQuery();

      // Add additional arguments as a fake condition.
      // XXX: this doesn't work... because PDO mandates that all bound arguments
      // are used on the query. TODO: Find a better way to do this.
      if (!empty($additional_arguments)) {
        // $query->where('1 = 1', $additional_arguments);
        // $count_query->where('1 = 1', $additional_arguments);
      }

      $start = microtime(TRUE);


      try {
        if ($this->pager->use_count_query() || !empty($view->get_total_rows)) {
          $this->pager->execute_count_query($count_query);
        }

        // Let the pager modify the query to add limits.
        $this->pager->pre_execute($query);

        if (!empty($this->limit) || !empty($this->offset)) {
          // We can't have an offset without a limit, so provide a very large limit instead.
          $limit  = intval(!empty($this->limit) ? $this->limit : 999999);
          $offset = intval(!empty($this->offset) ? $this->offset : 0);
          $query->range($offset, $limit);
        }

        $result = $query->execute();

        $view->result = array();
        foreach ($result as $item) {
          $view->result[] = $item;
        }

        $this->pager->post_execute($view->result);

        if ($this->pager->use_pager()) {
          $view->total_rows = $this->pager->get_total_items();
        }
      }
      catch (Exception $e) {
        $view->result = array();
        if (!empty($view->live_preview)) {
          drupal_set_message(time());
          drupal_set_message($e->getMessage(), 'error');
        }
        else {
          vpr('Exception in @human_name[@view_name]: @message', array('@human_name' => $view->human_name, '@view_name' => $view->name, '@message' => $e->getMessage()));
        }
      }

    }
    $view->execute_time = microtime(TRUE) - $start;
  }

  function add_signature(&$view) {
    $view->query->add_field(NULL, "'" . $view->name . ':' . $view->current_display . "'", 'view_name');
  }

  function get_aggregation_info() {
    // @todo -- need a way to get database specific and customized aggregation
    // functions into here.
    return array(
      'group' => array(
        'title' => t('Group results together'),
        'is aggregate' => FALSE,
      ),
      'count' => array(
        'title' => t('Count'),
        'method' => 'views_query_default_aggregation_method_simple',
        'handler' => array(
          'argument' => 'views_handler_argument_group_by_numeric',
          'field' => 'views_handler_field_numeric',
          'filter' => 'views_handler_filter_group_by_numeric',
          'sort' => 'views_handler_sort_group_by_numeric',
        ),
      ),
      'count_distinct' => array(
        'title' => t('Count DISTINCT'),
        'method' => 'views_query_default_aggregation_method_distinct',
        'handler' => array(
          'argument' => 'views_handler_argument_group_by_numeric',
          'field' => 'views_handler_field_numeric',
          'filter' => 'views_handler_filter_group_by_numeric',
          'sort' => 'views_handler_sort_group_by_numeric',
        ),
      ),
      'sum' => array(
        'title' => t('Sum'),
        'method' => 'views_query_default_aggregation_method_simple',
        'handler' => array(
          'argument' => 'views_handler_argument_group_by_numeric',
          'filter' => 'views_handler_filter_group_by_numeric',
          'sort' => 'views_handler_sort_group_by_numeric',
        ),
      ),
      'avg' => array(
        'title' => t('Average'),
        'method' => 'views_query_default_aggregation_method_simple',
        'handler' => array(
          'argument' => 'views_handler_argument_group_by_numeric',
          'filter' => 'views_handler_filter_group_by_numeric',
          'sort' => 'views_handler_sort_group_by_numeric',
        ),
      ),
      'min' => array(
        'title' => t('Minimum'),
        'method' => 'views_query_default_aggregation_method_simple',
        'handler' => array(
          'argument' => 'views_handler_argument_group_by_numeric',
          'filter' => 'views_handler_filter_group_by_numeric',
          'sort' => 'views_handler_sort_group_by_numeric',
        ),
      ),
      'max' => array(
        'title' => t('Maximum'),
        'method' => 'views_query_default_aggregation_method_simple',
        'handler' => array(
          'argument' => 'views_handler_argument_group_by_numeric',
          'filter' => 'views_handler_filter_group_by_numeric',
          'sort' => 'views_handler_sort_group_by_numeric',
        ),
      ),
    );
  }

  function get_result_entities($results, $relationship = NULL) {
    $base_table = $this->base_table;
    $base_table_alias = $base_table;

    if (!empty($relationship)) {
      foreach ($this->view->relationship as $current) {
        if ($current->alias == $relationship) {
          $base_table = $current->definition['base'];
          $base_table_alias = $relationship;
          break;
        }
      }
    }
    $table_data = views_fetch_data($base_table);

    // Bail out if the table has not specified the according entity-type.
    if (!isset($table_data['table']['entity type'])) {
      return FALSE;
    }
    $entity_type = $table_data['table']['entity type'];
    $info = entity_get_info($entity_type);
    $id_alias = $this->get_field_alias($base_table_alias, $info['entity keys']['id']);

    // Assemble the ids of the entities to load.
    $ids = array();
    foreach ($results as $key => $result) {
      if (isset($result->$id_alias)) {
        $ids[$key] = $result->$id_alias;
      }
    }

    $entities = entity_load($entity_type, $ids);
    // Re-key the array by row-index.
    $result = array();
    foreach ($ids as $key => $id) {
      $result[$key] = isset($entities[$id]) ? $entities[$id] : FALSE;
    }
    return array($entity_type, $result);
  }
}

function views_query_default_aggregation_method_simple($group_type, $field) {
  return strtoupper($group_type) . '(' . $field . ')';
}

function views_query_default_aggregation_method_distinct($group_type, $field) {
  $group_type = str_replace('_distinct', '', $group_type);
  return strtoupper($group_type) . '(DISTINCT ' . $field . ')';
}