public function getImportSpec()
    {
        $singleton = DataObject::singleton($this->objectClass);

        // get database columns (fieldlabels include fieldname as a key)
        // using $$includerelations flag as false, so that it only contain $db fields
        $fields = (array)$singleton->fieldLabels(false);

        // Merge relations
        $relations = array_merge(
            $singleton->hasOne(),
            $singleton->hasMany(),
            $singleton->manyMany()
        );

        // Ensure description is string (e.g. many_many through)
        foreach ($relations as $name => $desc) {
            if (!is_string($desc)) {
                $relations[$name] = $name;
            }
        }

        return [
            'fields' => $fields,
            'relations' => $relations,
        ];
    }