Case insensitive search using findoneby()

Problem is not at Symfony level but at your database level. Some of them are case sensitive and some are not. Yours is case sensitive apparently. To get results, no matter case, try following:

     $name = 'REd'; //case doesn't matter
     $colorMaster->createQueryBuilder('a')
        ->where('upper(a.name) = upper(:name)')
        ->setParameter('name', $name)
        ->getQuery()
        ->execute();