Simple tags system in Laravel 5.2

Question

I'm making simple tagging function in my laravel project. I've made table tags

id | tag

also I have table items

id | title | description

and third table item_tag which will hold the id of item and id of tag

In my Item model I've added this relation

public function tags() {

    return $this->belongsToMany('App\Tag', 'item_tag');
}

and the relation in Tag model

public function itemTags() {

    return $this->belongsToMany('App\Item', 'item_tag');

}

Item creating controller has create() for the view and store() for storing item

public function create(){

   $allTags = Tag::all();
   return view('items.create', compact('allTags'));       
}

public function store( ItemRequest $request ){

    $item = new Item;
    $item->title = $request['title'];
    $item->description = $request['description'];        
    $item->save();

    return redirect()->route('items');       
}

On form tags selection with multiple ( not sure if is correct way of doing it like this )

<div class="form-group">
     {!! Form::label('tags', 'Tags', array('class'=> 'col-sm-2 control-label')) !!}                        
     <div class="col-sm-10">
         <select name="tags[]" class="form-control select2" id="tags" multiple>
         @foreach($allTags as $tag)
              <option value="{!!$tag->id!!}">{!!$tag->tag!!}</option>
         @endforeach
         </select>
     </div>
</div> 

My question is how to grab and save tags id and item id in pivot table? And then show tags on the page on the item?

Update

in dd($item) I see this in relations

  #relations: array:3 [▼
    "tags" => Collection {#330 ▼
      #items: array:1 [▼
        0 => Tag {#329 ▼
          #table: "tags"
          #primaryKey: "id"
          #fillable: array:1 [▶]
          #connection: null
          #keyType: "int"
          #perPage: 15
          +incrementing: true
          +timestamps: true
          #attributes: array:10 [▼
            "id" => 5
            "tag" => "testTag"
            "title" => null
            "subtitle" => null
            "page_image" => null
            "meta_description" => null
            "layout" => null
            "reverse_direction" => null
            "created_at" => "2017-01-25 06:52:59"
            "updated_at" => "2017-01-25 06:52:59"
          ]
        }
      ]
    }
  ]

Answer 1

Usually, you want to detach all tags from an item and attach only ones that user has added in the form. In this case, use sync() method.

The sync method accepts an array of IDs to place on the intermediate table. Any IDs that are not in the given array will be removed from the intermediate table. So, after this operation is complete, only the IDs in the given array will exist in the intermediate table

For example:

$item = new Item;
$item->title = $request['title'];
$item->description = $request['description'];        
$item->save();

// If some tags are new, you should create them here first and get their IDs from a DB.

$item->tags()->sync($request->tags);