silverstripe-framework/ORM/Connect/MySQLQueryBuilder.php

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<?php
namespace SilverStripe\ORM\Connect;
use InvalidArgumentException;
use SilverStripe\ORM\Queries\SQLSelect;
/**
* Builds a SQL query string from a SQLExpression object
*
* @package framework
* @subpackage orm
*/
class MySQLQueryBuilder extends DBQueryBuilder {
/**
* Max number of rows allowed in MySQL
* @var string
*/
const MAX_ROWS = '18446744073709551615';
/**
* Return the LIMIT clause ready for inserting into a query.
*
* @param SQLSelect $query The expression object to build from
* @param array $parameters Out parameter for the resulting query parameters
* @return string The finalised limit SQL fragment
*/
public function buildLimitFragment(SQLSelect $query, array &$parameters) {
$nl = $this->getSeparator();
// Ensure limit is given
$limit = $query->getLimit();
if(empty($limit)) return '';
// For literal values return this as the limit SQL
if (!is_array($limit)) {
return "{$nl}LIMIT $limit";
}
// Assert that the array version provides the 'limit' key
if (!array_key_exists('limit', $limit) || ($limit['limit'] !== null && ! is_numeric($limit['limit']))) {
throw new InvalidArgumentException(
'MySQLQueryBuilder::buildLimitSQL(): Wrong format for $limit: '. var_export($limit, true)
);
}
if($limit['limit'] === null) {
$limit['limit'] = self::MAX_ROWS;
}
// Format the array limit, given an optional start key
$clause = "{$nl}LIMIT {$limit['limit']}";
if(isset($limit['start']) && is_numeric($limit['start']) && $limit['start'] !== 0) {
$clause .= " OFFSET {$limit['start']}";
}
return $clause;
}
}