Permalink
Fetching contributors…
Cannot retrieve contributors at this time
180 lines (163 sloc) 4.79 KB
<?php
/**
* @link http://www.yiiframework.com/
* @copyright Copyright (c) 2008 Yii Software LLC
* @license http://www.yiiframework.com/license/
*/
namespace yii\db;
use yii\base\BaseObject;
/**
* BatchQueryResult represents a batch query from which you can retrieve data in batches.
*
* You usually do not instantiate BatchQueryResult directly. Instead, you obtain it by
* calling [[Query::batch()]] or [[Query::each()]]. Because BatchQueryResult implements the [[\Iterator]] interface,
* you can iterate it to obtain a batch of data in each iteration. For example,
*
* ```php
* $query = (new Query)->from('user');
* foreach ($query->batch() as $i => $users) {
* // $users represents the rows in the $i-th batch
* }
* foreach ($query->each() as $user) {
* }
* ```
*
* @author Qiang Xue <qiang.xue@gmail.com>
* @since 2.0
*/
class BatchQueryResult extends BaseObject implements \Iterator
{
/**
* @var Connection the DB connection to be used when performing batch query.
* If null, the "db" application component will be used.
*/
public $db;
/**
* @var Query the query object associated with this batch query.
* Do not modify this property directly unless after [[reset()]] is called explicitly.
*/
public $query;
/**
* @var int the number of rows to be returned in each batch.
*/
public $batchSize = 100;
/**
* @var bool whether to return a single row during each iteration.
* If false, a whole batch of rows will be returned in each iteration.
*/
public $each = false;
/**
* @var DataReader the data reader associated with this batch query.
*/
private $_dataReader;
/**
* @var array the data retrieved in the current batch
*/
private $_batch;
/**
* @var mixed the value for the current iteration
*/
private $_value;
/**
* @var string|int the key for the current iteration
*/
private $_key;
/**
* Destructor.
*/
public function __destruct()
{
// make sure cursor is closed
$this->reset();
}
/**
* Resets the batch query.
* This method will clean up the existing batch query so that a new batch query can be performed.
*/
public function reset()
{
if ($this->_dataReader !== null) {
$this->_dataReader->close();
}
$this->_dataReader = null;
$this->_batch = null;
$this->_value = null;
$this->_key = null;
}
/**
* Resets the iterator to the initial state.
* This method is required by the interface [[\Iterator]].
*/
public function rewind()
{
$this->reset();
$this->next();
}
/**
* Moves the internal pointer to the next dataset.
* This method is required by the interface [[\Iterator]].
*/
public function next()
{
if ($this->_batch === null || !$this->each || $this->each && next($this->_batch) === false) {
$this->_batch = $this->fetchData();
reset($this->_batch);
}
if ($this->each) {
$this->_value = current($this->_batch);
if ($this->query->indexBy !== null) {
$this->_key = key($this->_batch);
} elseif (key($this->_batch) !== null) {
$this->_key = $this->_key === null ? 0 : $this->_key + 1;
} else {
$this->_key = null;
}
} else {
$this->_value = $this->_batch;
$this->_key = $this->_key === null ? 0 : $this->_key + 1;
}
}
/**
* Fetches the next batch of data.
* @return array the data fetched
*/
protected function fetchData()
{
if ($this->_dataReader === null) {
$this->_dataReader = $this->query->createCommand($this->db)->query();
}
$rows = [];
$count = 0;
while ($count++ < $this->batchSize && ($row = $this->_dataReader->read())) {
$rows[] = $row;
}
return $this->query->populate($rows);
}
/**
* Returns the index of the current dataset.
* This method is required by the interface [[\Iterator]].
* @return int the index of the current row.
*/
public function key()
{
return $this->_key;
}
/**
* Returns the current dataset.
* This method is required by the interface [[\Iterator]].
* @return mixed the current dataset.
*/
public function current()
{
return $this->_value;
}
/**
* Returns whether there is a valid dataset at the current position.
* This method is required by the interface [[\Iterator]].
* @return bool whether there is a valid dataset at the current position.
*/
public function valid()
{
return !empty($this->_batch);
}
}