title: Updating an Eloquent model with custom attributes
body: <p>I have a model that has two extra attributes which are not stored in the database, but contain request-specific information that I need. The values of these properties can be derived from the saved data inside the database, that's why they don't have their own columns in the table.</p>
  
  <p>When updating this model I see it tries to pass in the declared properties in <code>protected $attributes [...]</code> into the update query. Can this be disabled because obviously there are no columns for my properties in <code>$attributes</code> array.</p>
  
  <p>This is a part of my model:</p>
  
  <pre><code>&lt;?php
  
  namespace App;
  
  use Illuminate\Database\Eloquent\Model;
  use Illuminate\Support\Facades\DB;
  
  /**
   * Class SurveyQuestionAnswer
   * @package App
   */
  class SurveyQuestionAnswer extends Model
  {
      /**
       * @var array
       */
      protected $fillable = ['label', 'value', 'index'];
  
      protected $attributes = ['labelParsed', 'hasOneOrMoreParameters'];
  
      // more model code ...
  }
  </code></pre>
  
  <p>And when the update-method on the model is called I get this error:</p>
  
  <p><code>SQLSTATE[42S22]: Column not found: 1054 Unknown column '0' in 'field list' (SQL: insert into</code>survey_question_answers<code>(</code>0<code>,</code>1<code>,</code>label<code>,</code>value<code>,</code>index<code>,</code>survey_question_id<code>,</code>updated_at<code>,</code>created_at<code>) values (labelParsed, hasOneOrMoreParameters, My custom answer label, 1, 1, 23, 2016-01-14 08:01:32, 2016-01-14 08:01:32))</code></p>
  
  <p>As you can see it tries to put <code>labelParsed</code> and <code>hasOneOrMoreParameters</code> into the query. But I want to disable that behavior. How can this be done?</p>