Zend FR

class Module_Model_DbTable_Classe extends Zend_Db_Table_Abstract{
    protected $_name = 'table';
    protected $_primary = 'id';
}

class Backend_Model_Classe{
protected $id;
protected $champ1;
protected $champ2;
public function __construct(array $options = null){}

public function getMapper(){
        if (null === $this->_mapper)
            $this->setMapper(new Backend_Model_ClasseMapper());
        return $this->_mapper;
    }

    public function setMapper($mapper){
        $this->_mapper=$mapper;
        return $this;
    }

      public function getMaxId(){
        return $this->getMapper()->getMaxId();
    }

}

class Backend_Model_QuestionnaireVersionMapper{

    public function setDbTable($dbTable){
        if(is_string($dbTable)) {
            $dbTable = new $dbTable();
        }
        if(!$dbTable instanceof Zend_Db_Table_Abstract) {
            throw new Exception('Invalid table data gateway provided');
        }
        $this->_dbTable = $dbTable;
        return $this;
    }

    public function getDbTable(){
        if(null === $this->_dbTable) {
            $this->setDbTable('Backend_Model_DbTable_Classe');
        }
        return $this->_dbTable;
    }

      public function getMaxId(){
        $select = $this->getDbTable()->select()->setIntegrityCheck(false)->from(array('t'=>'table'),array('MAX(t.id) as maxId'));
        $resultSet = $this->getDbTable()->fetchRow($select);
        if(count($resultSet)==0) return 1;
        return $resultSet->maxId;
      }

}