带数据库的Typo3 ExtensionProblem:尽管有连接,但看不到值

I am trying to migrate my own extension from an older (typo3 6.2.31) version to the latest (Typo3 8.7.19). The extension includes a table with uploaded videos.

In my database the records are alle persistent.

I only can see a row for each video like in database, but without values. Using debugger utility I can see all attributes, like 'title'. But these are all empty except the uid.

I doublechecked the controller and the model and this looks fine to me. Maybe there are changes in the tca settings or ext_tables.php which I need to perform. What else can cause this problem?

Best Regards

Let me know if or witch code you need to see to give a more detailled answer and I will add it to my post

Class/Namespace Controller

namespace TYPO3\Videoverwaltung\Controller;

class VideoController extends 
\TYPO3\CMS\Extbase\Mvc\Controller\ActionController
{

Class/Namespace Model

namespace TYPO3\Videoverwaltung\Domain\Model;

class Video extends \TYPO3\CMS\Extbase\DomainObject\AbstractEntity
{

Class/Namespace VideoRepository

namespace TYPO3\Institutsvideoverwaltung\Domain\Repository;

class VideoRepository extends \TYPO3\CMS\Extbase\Persistence\Repository {

Thanks in advance.