The existing data required by the data writer could not be found - xenforo

Question

On my page for an add-on i am creating works perfectly well unless i try to update an existing row. `public function actionUpdate()
{
$visitor = XenForo_Visitor::getInstance();
$userName = $visitor['username'];
//Get the text that user wrote in the text box
$text3 = $this->_input->filterSingle('simple_text2', XenForo_Input::STRING);
$text4 = $this->_input->filterSingle('simple_text3', XenForo_Input::STRING);
//Create a instance of our DataWriter
$dwSimpleText = XenForo_DataWriter::create('MinecraftAdder_DataWriter_MinecraftAdder');
//Set the field with the data we filtered
$dwSimpleText->setExistingData('Name');
$dwSimpleText->set('Name', $text3);
$dwSimpleText->setExistingData('Rank');
$dwSimpleText->set('Rank', XenForo_Visitor::getUserId());
$dwSimpleText->setExistingData('UUID');
$dwSimpleText->set('UUID', $text4);
$dwSimpleText->setExistingData('UserID');
$dwSimpleText->set('UserID', $userName);
//Save in the database, please!
$dwSimpleText->save();
//Send a response to the user, so he know that everything went fine with this action
return $this->responseRedirect(
XenForo_ControllerResponse_Redirect::SUCCESS,
$this->getDynamicRedirect()
);
}`
I get the error The existing data required by the data writer could not be found. Does anyone know how to fix this?
My Addon page

Answer 1

Your usage of setExistingData is incorrect. That function must be given one of these two values:
The value of the Primary Key column(s) for the row you want to update
An array with all the data for the row you want to update
So in your case, seeing as you don't select the row in advance, you'd use option 1. Assuming UserID is your Primary Key column, your code would be:
public function actionUpdate() {
$visitor = XenForo_Visitor::getInstance();
$userName = $visitor['username'];
//Get the text that user wrote in the text box
$text3 = $this->_input->filterSingle('simple_text2', XenForo_Input::STRING);
$text4 = $this->_input->filterSingle('simple_text3', XenForo_Input::STRING);
//Create a instance of our DataWriter
$dwSimpleText = XenForo_DataWriter::create('MinecraftAdder_DataWriter_MinecraftAdder');
//Set the field with the data we filtered
$dwSimpleText->setExistingData($userName);
$dwSimpleText->set('Name', $text3);
$dwSimpleText->set('Rank', XenForo_Visitor::getUserId());
$dwSimpleText->set('UUID', $text4);
//Save in the database, please!
$dwSimpleText->save();
//Send a response to the user, so he know that everything went fine with this action
return $this->responseRedirect(
XenForo_ControllerResponse_Redirect::SUCCESS,
$this->getDynamicRedirect()
);
}
Some other tips:
If this actionUpdate may be accessed through a form only, you should add $this->_assertPostOnly(); on the top of the function to make sure the request was a POST request.
You may want to check if the Visitor's user_id is 0 so you don't save the information of guests. (Unless that's what you want of course)