Accessing the database

The TYPO3 database should always be accessed using the QueryBuilder of Doctrine. The ConnectionPool class should be injected via constructor injection and can then be used to create a QueryBuilder instance:

EXT:my_extension/Classes/Domain/Repository/MyTableRepository.php

<?php

declare(strict_types=1);

namespace MyVendor\MyExtension\Domain\Repository;

use TYPO3\CMS\Core\Database\ConnectionPool;

final class MyTableRepository
{
    private const TABLE_NAME = 'tx_myextension_domain_model_mytable';

    public function __construct(
        private readonly ConnectionPool $connectionPool,
    ) {}

    public function findSomething()
    {
        // Get a query builder for a table
        $queryBuilder = $this->connectionPool
            ->getQueryBuilderForTable(self::TABLE_NAME);
    }
}

See the Database chapter for more details.