Method _getAssetParentId

/**
 * Method to get the parent asset id for the record
 *
 * @param   Table    $table  A Table object (optional) for the asset parent
 * @param   integer  $id     The id (optional) of the content.
 *
 * @return  integer
 *
 * @since   1.6
 */
protected function _getAssetParentId(Table $table = null, $id = null)
{
    $assetId = null;
    // This is an article under a category.
    if ($this->catid) {
        $catId = (int) $this->catid;
        // Build the query to get the asset id for the parent category.
        $query = $this->_db->getQuery(true)->select($this->_db->quoteName('asset_id'))->from($this->_db->quoteName('#__categories'))->where($this->_db->quoteName('id') . ' = :catid')->bind(':catid', $catId, ParameterType::INTEGER);
        // Get the asset id from the database.
        $this->_db->setQuery($query);
        if ($result = $this->_db->loadResult()) {
            $assetId = (int) $result;
        }
    }
    // Return the asset id.
    if ($assetId) {
        return $assetId;
    } else {
        return parent::_getAssetParentId($table, $id);
    }
}