geno/wp-content/plugins/mailpoet/lib/Util/DBCollationChecker.php
2024-02-01 11:54:18 +00:00

46 lines
1.8 KiB
PHP

<?php declare(strict_types = 1);
namespace MailPoet\Util;
if (!defined('ABSPATH')) exit;
use MailPoetVendor\Doctrine\ORM\EntityManager;
class DBCollationChecker {
/** @var EntityManager */
private $entityManager;
public function __construct(
EntityManager $entityManager
) {
$this->entityManager = $entityManager;
}
/**
* If two columns have incompatible collations returns MySQL's COLLATE command to be used with the target table column.
* e.g. WHERE source_table.column = target_table.column COLLATE xyz
*
* In MySQL, if you have the same charset and collation in joined tables' columns it's perfect;
* if you have different charsets, utf8 and utf8mb4, it works too; but if you have the same charset
* with different collations, e.g. utf8mb4_unicode_ci and utf8mb4_unicode_520_ci, it will fail
* with an 'Illegal mix of collations' error.
*/
public function getCollateIfNeeded(string $sourceTable, string $sourceColumn, string $targetTable, string $targetColumn): string {
$connection = $this->entityManager->getConnection();
$sourceColumnData = $connection->executeQuery("SHOW FULL COLUMNS FROM $sourceTable WHERE Field = '$sourceColumn';")->fetchAllAssociative();
$sourceCollation = $sourceColumnData[0]['Collation'] ?? '';
$targetColumnData = $connection->executeQuery("SHOW FULL COLUMNS FROM $targetTable WHERE Field = '$targetColumn';")->fetchAllAssociative();
$targetCollation = $targetColumnData[0]['Collation'] ?? '';
if ($sourceCollation === $targetCollation) {
return '';
}
list($sourceCharset) = explode('_', $sourceCollation);
list($targetCharset) = explode('_', $targetCollation);
if ($sourceCharset === $targetCharset) {
return "COLLATE $sourceCollation";
}
return '';
}
}