How to understand entities, save, hasChanged

Read the error message carefully.
"Call to a member function fill() on null"
That is, $QgisResort is null.

Thank you Kenjis. It is my lack of understanding of entities. I thought that if QgisResort was empty and I fill it, it will treat it as new if I save it. Do I need to fill $QgisResort and then save? How should this work? Thank you again.

It seems you misunderstand something.

PHP Code:

$QgisResort = $this->QgisSkiResortModel->find($new_fill['id']); 


The Model::find() method returns null if the entity is not found.

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It seems you misunderstand something.

PHP Code:

$QgisResort = $this->QgisSkiResortModel->find($new_fill['id']); 


The Model::find() method returns null if the entity is not found.

I am trying to:
- insert new data if the entity doesn't exist
- update existing data if the entity exists

I am confused how to use find(), fill() save() hasChanged() to accomplish above. Very sorry but what is the basis logic to accomplish this?

I understand find(). It will be null if not found and means I should create a new entity to save. After that do I create a new entity and fill() to it and then save()?

If find() finds something, do I fill that entity object with fill() and check thereafter if hasChanged()? and then if hasChanged() i save() it?

Thank you.

I understand find().  It will be null if not found and means I should create a new entity to save.  After that do I create a new entity and fill() to it and then save()?

Yes.

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Thank you Kenjis.

It now works.

Something like this right? It now saves on new data, updates and doesnt do anthing if the record is not changed.

PHP Code:

foreach ($aa_winter_sports_points->features as $aa_winter_sports_point ){
        
            // Convert stdClass object to associative array in php
            // https://stackoverflow.com/questions/34428702/convert-stdclass-object-to-associative-array-in-php
            $data = array($aa_winter_sports_point->properties);
            $new_fill = json_decode(json_encode($data[0]), TRUE);
            
            // find() will return an entity $existing_data.  Works also in findAll();
            $QgisResort = $this->QgisSkiResortModel->find($new_fill['id']);
            
            //get list all permissable attributes that can go into the db
            $attributes = $this->QgisSkiResortModel->allowedFields;
           
            // filter new attributes in the new fill
            $attributes_matching_from_new_fill = array_filter($new_fill, function ($value, $key) use ($attributes) {
                if (in_array($key, $attributes)) {
                  return true;
                }
            }, ARRAY_FILTER_USE_BOTH);
            
            // create a new record
            if ($QgisResort === null){
                $newSkiResort = new \App\Entities\QgisSkiResortEntity();
                $newSkiResort->fill($attributes_matching_from_new_fill);
                $this->QgisSkiResortModel->save($newSkiResort);
                $resortNew++;
            // record exists
            } elseif($QgisResort){
                $QgisResort->fill($attributes_matching_from_new_fill);
                if ($QgisResort->hasChanged()){
                    if ($this->QgisSkiResortModel->save($attributes_matching_from_new_fill)){
                        $resortUpdated++;   
                    }
                }
                if (!$QgisResort->hasChanged()){
                    $resortNothingToUpdate++;
                    echo $QgisResort->id.'</br>';
                    echo $QgisResort->{'name:en'}.'</br>';
                    echo '</br>';
                }
            }
            
            $i++;
        }