symfony doctrine updatedAt createdAt updated_at created_at fields timestamp

EntityBase.php

<?php

namespace AppBundle\Mapping;

use Doctrine\ORM\Mapping as ORM;
use DateTime;

/**
 * Class EntityBase
 *
 * PHP version 7.1
 *
 * LICENSE: MIT
 *
 * @package    AppBundle\Mapping
 * @author     Lelle - Daniele Rostellato <[email protected]>
 * @license    MIT
 * @version    1.0.0
 * @since      File available since Release 1.0.0
 * @ORM\HasLifecycleCallbacks
 */
class EntityBase implements EntityBaseInterface
{
    /**
     * @var DateTime $created
     *
     * @ORM\Column(name="created_at", type="datetime", nullable=false)
     */
    protected $createdAt;

    /**
     * @var DateTime $updated
     *
     * @ORM\Column(name="updated_at", type="datetime", nullable=false)
     */
    protected $updatedAt;

    /**
     * @ORM\PrePersist
     * @ORM\PreUpdate
     */
    public function updatedTimestamps(): void
    {
        $dateTimeNow = new DateTime('now');

        $this->setUpdatedAt($dateTimeNow);

        if ($this->getCreatedAt() === null) {
            $this->setCreatedAt($dateTimeNow);
        }
    }

    public function getCreatedAt() :?DateTime
    {
        return $this->createdAt;
    }
    
    public function setCreatedAt(DateTime $createdAt): self
    {
        $this->createdAt = $createdAt;

        return $this;
    }

    public function getUpdatedAt() :?DateTime
    {
        return $this->updatedAt;
    }
    
    public function setUpdatedAt(DateTime $updatedAt): self
    {
        $this->updatedAt = $updatedAt;

        return $this;
    }
}

EntityBaseInterface.php

<?php

namespace AppBundle\Mapping;

use Doctrine\ORM\Mapping as ORM;
use DateTime;

/**
 * EntityBase Interface
 *
 * @author Lelle - Daniele Rostellato <[email protected]>
 */
interface EntityBaseInterface
{
    /**
     * @ORM\PrePersist
     * @ORM\PreUpdate
     */
    public function updatedTimestamps(): void;

    /**
     * Get createdAt
     *
     * @return null|DateTime
     */
    public function getCreatedAt(): ?DateTime

    /**
     * Set createdAt
     *
     * @param DateTime $createdAt
     * @return self
     */
    public function setCreatedAt(DateTime $createdAt): self
        
    /**
     * Get updatedAt
     *
     * @param DateTime $createdAt
     * @return self
     */
    public function getUpdatedAt(): ?DateTime

    /**
     * Set updatedAt
     *
     * @param DateTime $updatedAt
     * @return self
     */
    public function setUpdatedAt(DateTime $updatedAt): self
}

MyEntity.php

<?php

namespace AppBundle\Entity;

use Doctrine\ORM\Mapping as ORM;
use AppBundle\Mapping\EntityBase;

/**
 * MyEntity
 *
 * @ORM\HasLifecycleCallbacks
 */
class MyEntity extends EntityBase
{
    // ...
}