<?php
/**
* Zend Framework
*
* LICENSE
*
* This source file is subject to the new BSD license that is bundled
* with this package in the file LICENSE.txt.
* It is also available through the world-wide-web at this URL:
* http://framework.zend.com/license/new-bsd
* If you did not receive a copy of the license and are unable to
* obtain it through the world-wide-web, please send an email
* to license@zend.com so we can send you a copy immediately.
*
* @category Zend
* @package Zend_Paginator
* @copyright Copyright (c) 2005-2014 Zend Technologies USA Inc. (http://www.zend.com)
* @license http://framework.zend.com/license/new-bsd New BSD License
* @version $Id$
*/
/**
* @see Zend_Paginator_Adapter_Interface
*/
require_once 'Zend/Paginator/Adapter/Interface.php';
/**
* @see Zend_Db
*/
require_once 'Zend/Db.php';
/**
* @see Zend_Db_Select
*/
require_once 'Zend/Db/Select.php';
/**
* @category Zend
* @package Zend_Paginator
* @copyright Copyright (c) 2005-2014 Zend Technologies USA Inc. (http://www.zend.com)
* @license http://framework.zend.com/license/new-bsd New BSD License
*/
class Zend_Paginator_Adapter_DbSelect implements Zend_Paginator_Adapter_Interface
{
/**
* Name of the row count column
*
* @var string
*/
const ROW_COUNT_COLUMN = 'zend_paginator_row_count';
/**
* The COUNT query
*
* @var Zend_Db_Select
*/
protected $_countSelect = null;
/**
* Database query
*
* @var Zend_Db_Select
*/
protected $_select = null;
/**
* Total item count
*
* @var integer
*/
protected $_rowCount = null;
/**
* Identifies this adapter for caching purposes. This value will remain constant for
* the entire life of this adapter regardless of how many different pages are queried.
*
* @var string
*/
protected $_cacheIdentifier = null;
/**
* Constructor.
*
* @param Zend_Db_Select $select The select query
*/
public function __construct(Zend_Db_Select $select)
{
$this->_select = $select;
$this->_cacheIdentifier = md5($select->assemble());
}
/**
* Returns the cache identifier.
*
* @return string
*/
public function getCacheIdentifier()
{
return $this->_cacheIdentifier;
}
/**
* Sets the total row count, either directly or through a supplied
* query. Without setting this, {@link getPages()} selects the count
* as a subquery (SELECT COUNT ... FROM (SELECT ...)). While this
* yields an accurate count even with queries containing clauses like
* LIMIT, it can be slow in some circumstances. For example, in MySQL,
* subqueries are generally slow when using the InnoDB storage engine.
* Users are therefore encouraged to profile their queries to find
* the solution that best meets their needs.
*
* @param Zend_Db_Select|integer $totalRowCount Total row count integer
* or query
* @return Zend_Paginator_Adapter_DbSelect $this
* @throws Zend_Paginator_Exception
*/
public function setRowCount($rowCount)
{
if ($rowCount instanceof Zend_Db_Select) {
$columns = $rowCount->getPart(Zend_Db_Select::COLUMNS);
$countColumnPart = empty($columns[0][2])
? $columns[0][1]
: $columns[0][2];
if ($countColumnPart instanceof Zend_Db_Expr) {
$countColumnPart = $countColumnPart->__toString();
}
$rowCountColumn = $this->_select->getAdapter()->foldCase(self::ROW_COUNT_COLUMN);
// The select query can contain only one column, which should be the row count column
if (false === strpos($countColumnPart, $rowCountColumn)) {
/**
* @see Zend_Paginator_Exception
*/
require_once 'Zend/Paginator/Exception.php';
throw new Zend_Paginator_Exception('Row count column not found');
}
$result = $rowCount->query(Zend_Db::FETCH_ASSOC)->fetch();
$this->_rowCount = count($result) > 0 ? $result[$rowCountColumn] : 0;
} else if (is_integer($rowCount)) {
$this->_rowCount = $rowCount;
} else {
/**
* @see Zend_Paginator_Exception
*/
require_once 'Zend/Paginator/Exception.php';
throw new Zend_Paginator_Exception('Invalid row count');
}
return $this;
}
/**
* Returns an array of items for a page.
*
* @param integer $offset Page offset
* @param integer $itemCountPerPage Number of items per page
* @return array
*/
public function getItems($offset, $itemCountPerPage)
{
$this->_select->limit($itemCountPerPage, $offset);
return $this->_select->query()->fetchAll();
}
/**
* Returns the total number of rows in the result set.
*
* @return integer
*/
public function count()
{
if ($this->_rowCount === null) {
$this->setRowCount(
$this->getCountSelect()
);
}
return $this->_rowCount;
}
/**
* Get the COUNT select object for the provided query
*
* TODO: Have a look at queries that have both GROUP BY and DISTINCT specified.
* In that use-case I'm expecting problems when either GROUP BY or DISTINCT
* has one column.
*
* @return Zend_Db_Select
*/
public function getCountSelect()
{
/**
* We only need to generate a COUNT query once. It will not change for
* this instance.
*/
if ($this->_countSelect !== null) {
return $this->_countSelect;
}
$rowCount = clone $this->_select;
$rowCount->__toString(); // Workaround for ZF-3719 and related
$db = $rowCount->getAdapter();
$countColumn = $db->quoteIdentifier($db->foldCase(self::ROW_COUNT_COLUMN));
$countPart = 'COUNT(1) AS ';
$groupPart = null;
$unionParts = $rowCount->getPart(Zend_Db_Select::UNION);
/**
* If we're dealing with a UNION query, execute the UNION as a subquery
* to the COUNT query.
*/
if (!empty($unionParts)) {
$expression = new Zend_Db_Expr($countPart . $countColumn);
$rowCount = $db
->select()
->bind($rowCount->getBind())
->from($rowCount, $expression);
} else {
$columnParts = $rowCount->getPart(Zend_Db_Select::COLUMNS);
$groupParts = $rowCount->getPart(Zend_Db_Select::GROUP);
$havingParts = $rowCount->getPart(Zend_Db_Select::HAVING);
$isDistinct = $rowCount->getPart(Zend_Db_Select::DISTINCT);
/**
* If there is more than one column AND it's a DISTINCT query, more
* than one group, or if the query has a HAVING clause, then take
* the original query and use it as a subquery os the COUNT query.
*/
if (($isDistinct && ((count($columnParts) == 1 && $columnParts[0][1] == Zend_Db_Select::SQL_WILDCARD)
|| count($columnParts) > 1)) || count($groupParts) > 1 || !empty($havingParts)) {
$rowCount->reset(Zend_Db_Select::ORDER);
$rowCount = $db
->select()
->bind($rowCount->getBind())
->from($rowCount);
} else if ($isDistinct) {
$part = $columnParts[0];
if ($part[1] !== Zend_Db_Select::SQL_WILDCARD && !($part[1] instanceof Zend_Db_Expr)) {
$column = $db->quoteIdentifier($part[1], true);
if (!empty($part[0])) {
$column = $db->quoteIdentifier($part[0], true) . '.' . $column;
}
$groupPart = $column;
}
} else if (!empty($groupParts)) {
$groupPart = $db->quoteIdentifier($groupParts[0], true);
}
/**
* If the original query had a GROUP BY or a DISTINCT part and only
* one column was specified, create a COUNT(DISTINCT ) query instead
* of a regular COUNT query.
*/
if (!empty($groupPart)) {
$countPart = 'COUNT(DISTINCT ' . $groupPart . ') AS ';
}
/**
* Create the COUNT part of the query
*/
$expression = new Zend_Db_Expr($countPart . $countColumn);
$rowCount->reset(Zend_Db_Select::COLUMNS)
->reset(Zend_Db_Select::ORDER)
->reset(Zend_Db_Select::LIMIT_OFFSET)
->reset(Zend_Db_Select::GROUP)
->reset(Zend_Db_Select::DISTINCT)
->reset(Zend_Db_Select::HAVING)
->columns($expression);
}
$this->_countSelect = $rowCount;
return $rowCount;
}
}