How to add a base field to broken link entity?

I want to add a base field to broken_link entity. I have written the following code.

function mymodule_entity_base_field_info(\Drupal\Core\Entity\EntityTypeInterface $entity_type) {
  if ($entity_type->id() === 'broken_link') {
    $fields = [];
    $fields['broken_link_page_title'] = BaseFieldDefinition::create('string')
      ->setName('Page title')
      ->setLabel('Page title')
      ->setConstraints([
        'type' => 'varchar',
        'length' => 255,
      ])
        ->setDescription(t('Page title which contains broken link.'));
    return $fields;
  }
}
function mymodule_entity_presave(EntityInterface $entity) {
  if ($entity->getEntityTypeId() == 'broken_link') {
    $entity->set('broken_link_page_title', 'testing');
  }
}

I can see my new field in views. But I can't see my new field in the broken link base table in database.
Also the value is not storing in the hook_entity_presave.

Is there any specific method to add a base field to this broken_link entity?