Answer.php

<?php

namespace AppBundle\Entity;

use Doctrine\ORM\Mapping as ORM;

/**
 * Answer
 * @ORM\Table(name="answer")
 */
class Answer
{
	/**
	 * @ORM\Column(name="id", type="integer")
	 * @ORM\Id
	 */
	private $id;
	
	/**
	 * @ORM\Column(name="content", type="string", nullable=false)
	 */
	private $content;
	
	/**
	 * @ORM\OneToOne(targetEntity="AppBundle\Entity\Question", inversedBy="answer")
	 * @ORM\JoinColumns({
	 *   @ORM\JoinColumn(name="question_id", referencedColumnName="id", unique=true)
	 * })
	 */
	private $question;
	
	/**
	 * Get id
	 * @return string
	 */
	public function getId()
	{
		return $this->id;
	}
	
	/**
	 * Set content
	 *
	 * @param string $content
	 *
	 * @return Answer
	 */
	public function setContent($content)
	{
		$this->content = $content;
		
		return $this;
	}
	
	/**
	 * Get content
	 * @return string
	 */
	public function getContent()
	{
		return $this->content;
	}
	
	/**
	 * Set question
	 *
	 * @param Question $question
	 *
	 * @return Answer
	 */
	public function setQuestion(Question $question = null)
	{
		$this->question = $question;
		
		return $this;
	}
	
	/**
	 * Get question
	 * @return Question
	 */
	public function getQuestion()
	{
		return $this->question;
	}
}

Question.php

<?php

namespace AppBundle\Entity;

use Doctrine\ORM\Mapping as ORM;

/**
 * @ORM\Table(name="question")
 */
class Question
{
	/**
	 * @ORM\Column(name="id", type="integer")
	 * @ORM\Id
	 */
	private $id;
	
	/**
	 * @ORM\Column(name="content", type="string", nullable=true)
	 */
	private $content;
	
	/**
	 * @ORM\OneToOne(targetEntity="AppBundle\Entity\Answer", mappedBy="question")
	 */
	private $answer;
	
	/**
	 * Set content
	 *
	 * @param string $content
	 *
	 * @return Question
	 */
	public function setContent($content)
	{
		$this->content = $content;
		
		return $this;
	}
	
	/**
	 * Get content
	 * @return string
	 */
	public function getContent()
	{
		return $this->content;
	}
	
	/**
	 * Get id
	 * @return string
	 */
	public function getId()
	{
		return $this->id;
	}
	
	/**
	 * Set answer
	 *
	 * @param Answer $answer
	 *
	 * @return Question
	 */
	public function setAnswer(Answer $answer = null)
	{
		$this->answer = $answer;
		
		return $this;
	}
	
	/**
	 * Get answer
	 * @return Answer
	 */
	public function getAnswer()
	{
		return $this->answer;
	}
}