mirror of
https://github.com/silverstripe/silverstripe-framework
synced 2024-10-22 14:05:37 +02:00
57 lines
1.5 KiB
PHP
57 lines
1.5 KiB
PHP
<?php
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/**
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* Builds a SQL query string from a SQLExpression object
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*
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* @package framework
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* @subpackage model
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*/
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class MySQLQueryBuilder extends DBQueryBuilder {
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/**
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* Max number of rows allowed in MySQL
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* @var string
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*/
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const MAX_ROWS = '18446744073709551615';
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/**
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* Return the LIMIT clause ready for inserting into a query.
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*
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* @param SQLSelect $query The expression object to build from
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* @param array $parameters Out parameter for the resulting query parameters
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* @return string The finalised limit SQL fragment
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*/
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public function buildLimitFragment(SQLSelect $query, array &$parameters) {
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$nl = $this->getSeparator();
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// Ensure limit is given
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$limit = $query->getLimit();
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if(empty($limit)) return '';
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// For literal values return this as the limit SQL
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if (!is_array($limit)) {
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return "{$nl}LIMIT $limit";
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}
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// Assert that the array version provides the 'limit' key
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if (!array_key_exists('limit', $limit) || ($limit['limit'] !== null && ! is_numeric($limit['limit']))) {
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throw new InvalidArgumentException(
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'MySQLQueryBuilder::buildLimitSQL(): Wrong format for $limit: '. var_export($limit, true)
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);
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}
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if($limit['limit'] === null) {
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$limit['limit'] = self::MAX_ROWS;
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}
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// Format the array limit, given an optional start key
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$clause = "{$nl}LIMIT {$limit['limit']}";
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if(isset($limit['start']) && is_numeric($limit['start']) && $limit['start'] !== 0) {
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$clause .= " OFFSET {$limit['start']}";
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}
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return $clause;
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}
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}
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