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