Faq.php

<?php

namespace XXXX\MediaToolBundle\Entity;

use Doctrine\ORM\Mapping as ORM;


/**
 * @ORM\Entity
 * @ORM\Table(name="faqs")
 */
class Faq{
	/**
	 * @ORM\Id
	 * @ORM\Column(type="bigint")
	 * @ORM\GeneratedValue(strategy="AUTO")
	 */
	protected $id;
	
	/**
	 * @ORM\Column(type="string")
	 */
	protected $question;
	
	/**
	 * @ORM\Column(type="string")
	 */
	protected $answer;
	
    /**
     * @ORM\ManyToOne(targetEntity="FaqCategory", inversedBy="faqs")
     * @ORM\JoinColumn(onDelete="SET NULL")
     */
    private $category;

	/**
	 * @ORM\Column(type="datetime", columnDefinition="TIMESTAMP DEFAULT CURRENT_TIMESTAMP")
	 */
	protected $timeCreated;
	


    public function __toString()
    {
      return $this->getQuestion();
    }

FaqAdmin.php

<?php

namespace XXXX\MediaToolBundle\Admin;

use Sonata\AdminBundle\Admin\Admin;
use Sonata\AdminBundle\Form\FormMapper;
use Sonata\AdminBundle\Datagrid\DatagridMapper;
use Sonata\AdminBundle\Datagrid\ListMapper;
use Sonata\AdminBundle\Show\ShowMapper;
use Sonata\AdminBundle\Route\RouteCollection;



use Knp\Menu\ItemInterface as MenuItemInterface;

use XXXX\MediaToolBundle\Entity\Faq;
use XXXX\MediaToolBundle\Entity\FaqCategory;

class FaqAdmin extends Admin
{
    
	
	
    /**
     * @param \Sonata\AdminBundle\Show\ShowMapper $showMapper
     *
     * @return void
     */
    protected function configureShowField(ShowMapper $showMapper)
    {
        $showMapper
            ->add('question')
            ->add('answer')
            ->add('category', 'sonata_type_model')
        ;
    }

    /**
     * @param \Sonata\AdminBundle\Form\FormMapper $formMapper
     *
     * @return void
     */
    protected function configureFormFields(FormMapper $formMapper)
    {
        $formMapper
            ->with('Allgemein')
            	->add('question')
            	->add('answer')
            ->end()
             ->with('FAQs')
                ->add('faqs', 'sonata_type_model', array('expanded' => true))
            ->end()
        ;
    }

    /**
     * @param \Sonata\AdminBundle\Datagrid\ListMapper $listMapper
     *
     * @return void
     */
    protected function configureListFields(ListMapper $listMapper)
    {
        $listMapper
            ->addIdentifier('id')
            ->add('question')
            ->add('answer')
            ->add('category')
           ->add('_action', 'actions', array(
                'actions' => array(
                    'view' => array(),
                    'edit' => array(),
                    'delete' => array(),
                )
            ))
        ;
    }		

    /**
     * @param \Sonata\AdminBundle\Datagrid\DatagridMapper $datagridMapper
     *
     * @return void
     */
    protected function configureDatagridFilters(DatagridMapper $datagridMapper)
    {
        $datagridMapper
            ->add('question')
            ->add('answer')
        ;
    }
}

FaqCategory.php

<?php

namespace XXXX\MediaToolBundle\Entity;

use Doctrine\ORM\Mapping as ORM;

/**
 * @ORM\Entity
 * @ORM\Table(name="faqcategories")
 */
class FaqCategory{
    /**
	 * @ORM\Id
	 * @ORM\Column(type="bigint")
	 * @ORM\GeneratedValue(strategy="AUTO")
	 */
	protected $id;
	

    /**
     * @ORM\Column(type="string")
     */
    protected $name;
    
    /**
     * @ORM\Column(type="string")
     */
    protected $icon;

    /**
     * @ORM\OneToMany(targetEntity="Faq", mappedBy="category")
     * @ORM\JoinColumn(nullable=false)
     */
    private $faqs;


	/**
	 * @ORM\Column(type="datetime", columnDefinition="TIMESTAMP DEFAULT CURRENT_TIMESTAMP")
	 */
	protected $timeCreated;
	

    public function __toString()
    {
      return (string)$this->getName();
    }
 
}