update guide about tabular input forms

docs/guide/input-forms.md

@@ -115,14 +115,28 @@ Handling multiple models with a single form
 > Note: This section is under development.
 
 Sometimes you need to handle multiple models of the same kind in a single form. For example, multiple settings where
-each setting is stored as name-value and is represented by `Setting` model. This kind of form is also often
-referred to as "tabular input". In contrast to this, handling different models of different kind, is handled in the section
+each setting is stored as a name-value pair and is represented by a `Setting` [active record](db-active-record.md) model.
+This kind of form is also often referred to as "tabular input".
+In contrast to this, handling different models of different kind, is handled in the section
 [Complex Forms with Multiple Models](input-multiple-models).
 
-
 The following shows how to implement tabular input with Yii.
 
-Let's start with controller action:
+There are three different situations to cover, which have to be handled slightly different:
+- Updating a fixed set of records from the database
+- Creating a dynamic set of new records
+- Updating, creating and deleting of records on one page
+
+In contrast to the single model forms explained before, we are working with an array of models now.
+This array is passed to the view to display the input fields for each model in a table like style and we
+will use helper methods of [[yii\base\Model]] that allow loading and validating multiple models at once:
+
+- [[yii\base\Model::loadMultiple()|Model::loadMultiple()]] load post data into an array of models.
+- [[yii\base\Model::validateMultiple()|Model::validateMultiple()]] validates an array of models.
+
+### Updating a fixed set of records
+
+Let's start with the controller action:
 
 ```php
 <?php
@@ -146,7 +160,6 @@ class SettingsController extends Controller
             foreach ($settings as $setting) {
                 $setting->save(false);
             }
-
             return $this->redirect('index');
         }
 
@@ -155,10 +168,12 @@ class SettingsController extends Controller
 }
 ```
 
-In the code above we're using `indexBy` when retrieving models from the database to populate an array indexed by model ids.
-These will be later used to identify form fields. `loadMultiple` fills multiple models with the form data coming from POST
-and `validateMultiple` validates all models at once. In order to skip validation when saving we're passing `false` as
-a parameter to `save`.
+In the code above we're using [[yii\db\ActiveQuery::indexBy()|indexBy()]] when retrieving models from the database to populate an array indexed by models primary keys.
+These will be later used to identify form fields. [[yii\base\Model::loadMultiple()|Model::loadMultiple()]] fills multiple
+models with the form data coming from POST
+and [[yii\base\Model::validateMultiple()|Model::validateMultiple()]] validates all models at once.
+As we have validated our models before, using `validateMultiple()`, we're now passing `false` as
+a parameter to [[yii\db\ActiveRecord::save()|save()]] to not run validation twice.
 
 Now the form that's in `update` view:
 
@@ -170,11 +185,37 @@ use yii\widgets\ActiveForm;
 $form = ActiveForm::begin();
 
 foreach ($settings as $index => $setting) {
-    echo Html::encode($setting->name) . ': ' . $form->field($setting, "[$index]value");
+    echo $form->field($setting, "[$index]value")->label($setting->name);
 }
 
 ActiveForm::end();
 ```
 
 Here for each setting we are rendering name and an input with a value. It is important to add a proper index
-to input name since that is how `loadMultiple` determines which model to fill with which values.
+to input name since that is how [[yii\base\Model::loadMultiple()|Model::loadMultiple()]] determines which model to fill with which values.
+
+### Creating a dynamic set of new records
+
+Creating new records is similar to updating except the part where we instantiate the models:
+
+```php
+public function actionCreate()
+{
+    $count = count(Yii::$app->request->post('Setting', []));
+    $settings = [new Setting()];
+    for($i = 1; $i < $count; $i++) {
+        $settings[] = new Setting();
+    }
+
+    // ...
+}
+```
+
+Here we create an initial `$settings` array containing one model by default and adding more models for each line of input
+we may have received.
+
+In the view you can use javascript to add new input lines dynamically.
+
+### Combining Update, Create and Delete on one page
+
+TBD