Query optimization PHP for string concatination
For now, one solution is to concatenate the options into a string while the answer is persisted. This is part of my FormToArrayTransformer:

switch ($_question-&gt;getFormField()-&gt;getType()) {
    case FormField::CHOICE:
        $content = '';

        foreach($answer as $_key=&gt;$option) {
            $surveyAnswer-&gt;addFormOption($option);
            if ($_key == 0) {
                $content .= $option-&gt;getName();
            } else {
                $content .= ', ' . $option-&gt;getName();
            }
        }

        $surveyAnswer-&gt;setContent($content);
        break;


Note that now both the FormOption entities and their string representation is stored. When viewing you don't have to iterate over the options anymore but simply calling answer.getContent() will do. This saved me 2300 queries in a table for 200 forms. 

I am still unsure why this is so.