The DB layer Writing a custom driver Query

The query part will help you to search for stuff in the DB. Let's have a look on the code:

<?php

namespace Nuntius\Db\RethinkDB;

use Nuntius\Db\DbQueryHandlerInterface;
use r\Exceptions\RqlException;
use r\ValuedQuery\RVar;

/**
 * RethinkDB query handler.
 */
class RethinkDbQueryHandler implements DbQueryHandlerInterface {

  /**
   * {@inheritdoc}
   */
  public function table($table) {
    $this->table = $table;

    return $this;
  }

  /**
   * {@inheritdoc}
   */
  public function condition($property, $value, $operator = '=') {
    $this->conditions[] = [
      'property' => $property,
      'value' => $value,
      'operator' => $operator,
    ];

    return $this;
  }

  /**
   * {@inheritdoc}
   */
  public function pager($start, $length) {
    $this->range = [
      'start' => $start,
      'length' => $length,
    ];

    return $this;
  }

  /**
   * {@inheritdoc}
   */
  public function orderBy($field, $direction) {
    $this->sort[] = [
      'field' => $field,
      'direction' => $direction,
    ];
    return $this;
  }

  /**
   * Set the mode of the changes flag.
   *
   * @param bool $mode
   *   The mode of the flag.
   *
   * @return RethinkDbQueryHandler
   *   The current instance.
   */
  public function setChanges($mode = TRUE) {
    $this->changes = $mode;

    return $this;
  }

  /**
   * Return the changes flag.
   *
   * @return bool
   */
  public function getChanges() {
    return $this->changes;
  }

  /**
   * {@inheritdoc}
   */
  public function execute() {
    $query = \r\table($this->table);

    if ($this->conditions) {
      foreach ($this->conditions as $condition) {

        $operator = !empty($condition['operator']) ? $condition['operator'] : '=';
        if (!in_array($operator, array_keys($this->operators))) {
          throw new RqlException("The operator {$operator} does not allowed. Only " . implode(', ', array_keys($this->operators)));
        }
        if ($operator == 'IN') {
          $row = function(RVar $doc) use ($condition) {
            return \r\expr($condition['value'])->contains($doc->getField($condition['property']));
          };
        }
        else {
          $row = \r\row($condition['property'])->{$this->operators[$operator]}($condition['value']);
        }

        $query = $query->filter($row);
      }
    }

    if ($this->range) {
      $query = $query->slice($this->range['start'], $this->range['length']);
    }

    if ($this->sort) {
      foreach ($this->sort as $sort) {
        $sort['field'] = empty($sort['field']) ? 'id' : $sort['field'];
        $sort_object = $sort['direction'] == 'ASC' ? \r\asc($sort['field']) : \r\desc($sort['field']);
        $query = $query->orderBy($sort_object);
      }
    }

    if ($this->changes) {
      return $query->changes()->run($this->rethinkDB->getConnection());
    }

    $items = [];

    foreach ($query->run($this->rethinkDB->getConnection()) as $item) {
      $item_copy = $item->getArrayCopy();

      $items[] = $item_copy;
    }

    $this->cleanUp();

    return $items;
  }

  /**
   * {@inheritdoc}
   */
  public function cleanUp() {
    $this->table = '';
    $this->conditions = [];
    $this->sort = [];
    $this->range = [];
  }

}

Each method is pretty explained in the docs and name.

Except for the cleanUp(). That's one is important since there are parts that use the same object to query the DB. The clean up method remove query settings from previous and promise the query will be done with out any issues.