class AggregatorFeed

class AggregatorFeed extends DrupalSqlBase {
    
    /**
     * {@inheritdoc}
     */
    public function query() {
        return $this->select('aggregator_feed', 'af')
            ->fields('af');
    }
    
    /**
     * {@inheritdoc}
     */
    public function fields() {
        $fields = [
            'fid' => $this->t('The feed ID.'),
            'title' => $this->t('Title of the feed.'),
            'url' => $this->t('URL to the feed.'),
            'refresh' => $this->t('Refresh frequency in seconds.'),
            'checked' => $this->t('Last-checked unix timestamp.'),
            'link' => $this->t('Parent website of the feed.'),
            'description' => $this->t("Parent website's description of the feed."),
            'image' => $this->t('An image representing the feed.'),
            'etag' => $this->t('Entity tag HTTP response header.'),
            'modified' => $this->t('When the feed was last modified.'),
            'block' => $this->t("Number of items to display in the feed's block."),
        ];
        if ($this->getModuleSchemaVersion('system') >= 7000) {
            $fields['queued'] = $this->t('Time when this feed was queued for refresh, 0 if not queued.');
        }
        return $fields;
    }
    
    /**
     * {@inheritdoc}
     */
    public function getIds() {
        $ids['fid']['type'] = 'integer';
        return $ids;
    }

}