Webiny\Component\Entity\AbstractEntity::populateAttribute PHP Method

    private function populateAttribute($attributeName, AbstractAttribute $entityAttribute, $validation, $data, $fromDb)
    {
        // Skip population of protected attributes if data is not coming from DB
        if (!$fromDb && $entityAttribute->getSkipOnPopulate()) {
            return;
        }
        // Dynamic attributes from database should be populated without any checks, and skipped otherwise
        if ($this->isInstanceOf($entityAttribute, AttributeType::DYNAMIC) && isset($data[$attributeName])) {
            $entityAttribute->setValue($data[$attributeName], $fromDb);
            return;
        }
        /**
         * Check if attribute is required and it's value is set or maybe value was already assigned
         */
        if (!$fromDb && $entityAttribute->isRequired() && !isset($data[$attributeName]) && !$entityAttribute->hasValue()) {
            $message = $entityAttribute->getValidationMessages('required');
            if (!$message) {
                $message = ValidationException::REQUIRED;
            }
            $ex = new ValidationException(ValidationException::VALIDATION_FAILED);
            $ex->addError($attributeName, $message, []);
            $validation[$attributeName] = $ex;
            return;
        }
        /**
         * In case it is an update - if the attribute is not in new $data, it's no big deal, we already have the previous value.
         */
        $dataIsSet = array_key_exists($attributeName, $data);
        if (!$dataIsSet && $this->exists()) {
            return;
        }
        $canPopulate = !$this->exists() || $fromDb || !$entityAttribute->getOnce();
        if ($dataIsSet && $canPopulate) {
            $dataValue = $data[$attributeName];
            try {
                $entityAttribute->setValue($dataValue, $fromDb);
            } catch (ValidationException $e) {
                $validation[$attributeName] = $e;
            }
        }
    }