Call to undefined method Application_Model_DbTable_Projects::lastInsertId() - zend-framework

Question

I want to retrieve the id of the last inserted row. This is the code I use in the mapper:
public function save(Application_Model_Projects $project)
{
$data = array(
'id_user' => $project->getIdUser(),
'project_name' => $project->getProjectName(),
'project_description' => $project->getProjectDescription(),
'due_date' => $project->getDueDate(),
'id_customer' => $project->getIdCustomer()
);
if(($id = $project->getId()) === null) {
unset($data['id']);
$this->getDbTable()->insert($data);
return $this->getDbTable()->lastInsertId();
}else {
$this->getDbTable()->update($data, array('id = ?', (int) $id));
return $id;
}
}
According to the code above, it should return the id of the object. It is either the id after insertion or the current id.
The code where I use this function:
$currentUser = new Application_Model_UserAuth();
$project = new Application_Model_Projects();
$project->setProjectName($formValues['projectName'])
->setProjectDescription($formValues['projectDescription'])
->setDueDate(date("Y-m-d",strtotime($formValues['dueDate'])))
->setIdCustomer($formValues['assignCustomer'])
->setIdUser($currentUser->id);
$projectMapper = new Application_Model_ProjectsMapper();
$idProject = $projectMapper->save($project);
The error I get is:
Fatal error: Call to undefined method Application_Model_DbTable_Projects::lastInsertId()
What is wrong with this? Shouldn't that return the last id? Because it is triggered upon insertion. In another sequence of code I call the lastInsertId: $Zend_Db_Table::getDefaultAdapter()->lastInsertId(). The only difference is that now I call lastInsertIt on a dbTable, that extends Zend_Db_Table_Abstract.

Answer 1

The answer to my question above is that I should call getAdapter() before lastInsertId().
Updated code:
if(($id = $project->getId()) === null) {
unset($data['id']);
$this->getDbTable()->insert($data);
return $this->getDbTable()->getAdapter()->lastInsertId();
}

Answer 2

If it is an single-column Primary Key the return value is lastInsertId by default, so you also can use this:
return $this->getDbTable()->insert($data);