Various tips and tricks

• Use Find usages of PhpStorm for examples! The source code of the Core is a great way to learn how specific methods of the API are used. In PhpStorm it is extremely helpful to right-click on a single method and list all method usages with Find usages. This is especially handy to quickly see usage examples for complex methods like join() from the query builder.

• INSERT, UPDATE and DELETE statements are often better to read and write using the Connection object instead of the query builder.

• SELECT DISTINCT aField is not supported but can be substituted with a ->groupBy('aField').

• getSql() and executeQuery() / executeStatement() can be used after each other during development to simplify debugging:

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

  $queryBuilder
      ->select('uid')
      ->from('tt_content')
      ->where(
          $queryBuilder->expr()->eq(
              'bodytext',
              $queryBuilder->createNamedParameter('lorem')
          )
      );
  
  debug($queryBuilder->getSql());
  
  $result = $queryBuilder->executeQuery();
  

• Doctrine DBAL throws exceptions if something goes wrong when calling executeQuery() or executeStatement(). The exception type is \Doctrine\DBAL\Exception, which can be caught and transferred to a better error message if the application should expect query errors. Note that this is not good habit and often indicates an architectural flaw in the application at a different layer.

• count() <database-query-builder-count> query types using the query builder normally call ->fetchOne() to receive the count value. The count() method of the Connection object does this automatically and returns the result of the count value directly.