Symfony2 1:M / 1:1 Relationship and Sonata Admin Form Rerence: - https://github.com/sonata-project/SonataAdminBundle/issues/1254 - http://sonata-project.org/bundles/admin/master/doc/reference/form_types.html

Person

<?php
//...
class Person
{
  /* @var \Doctrine\Common\Collections\Collection */
  private $talents
  
  /* @var string */
  private $gender
  
  /* @var string */
  private $name
  
  /* Constructor */
  public function __contruct()
  {
    $this->talents = new \Doctrine\Common\Collections\ArrayCollection();
  }
  
  /* Add talents
  * @param \Company\MyBundle\Entity\Talent $talents */
  public function addTalent(\Company\MyBundle\Entity\Talent $talents)
  {
    $talents->setPerson($this);
    $this->talents->add($talents);  
  }
  
  /* Set talents
  * @param \Company\MyBundle\Entity\Talent $talents 
  * @return Person  */
  public function setTalents(\Company\MyBundle\Entity\Talent $talents)
  {
    $this->talents = new \Doctrine\Common\Collections\ArrayCollection();
    
    foreach($talents as $talent)
    {
      $this->addTalent($talent);
    }
    return $this;
  }
  
  /* Remove farm
  * @param \Company\MyBundle\Entity\Talent $talent */ 
  public function removeTalent(\Company\MyBundle\Entity\Talent $talent)
  {
    $this->talents->removeElement($talent);
  }
  
  // ...
  // setter & getter for $gender and $name
  /* */
  public static function getGenderList()
  {
    return array(
      'male' => 'Male',
      'female' => 'Female'
    );
  }
  
  /* */
  public static function getGenderValues(){
    return array(self::getGenderList());
  }
  
  /* @var string */
  public function __toString(){
    return $this->getName()?:'';
  }
}

PersonAdmin

<?php
//...
class PersonAdmin extends Admin
{
  //...
  /* @param FormMapper $formMapper */
  protected function configureFormFields(FormMapper $formMapper)
  {
    $formMapper
      ->add('name')
      ->add('gender', 'choice', array(
          'choices' => Person::getGenderList(),
          //'expanded' => true, 
        ))
      ->add('talents', 'sonata_type_collection', array('required' => false), array(
          'edit' => 'inline',
          'inline' => 'table',
          'sortable' => 'position',
        ))
    ;
  }
  //...
}