选中/取消选中复选框值时更新数据透视表

Question

I have a form containing checkboxes that have values/lists of holiday names.

The situation is a many-to-many relationship where One ZONE can apply One/Many HOLIDAY and One HOLIDAY can be applied by One/Many ZONE.

So, there is a pivot table named Zone_Holidays :

----------------------- 
Zone_ID  |  Holiday_ID
-----------------------   
   1     |      3    
   1     |      2    
   2     |      1    
   2     |      2    
   2     |      3    
   3     |      2
-----------------------

The RESULT of PIVOT table comes out when HOLIDAY is CHECKED according to zone.

For the first time input, there's no problem. The problem is, when I want to UPDATE holiday for zone by clicking (checked/unchecked) on the checkbox, there is no change.

The way I have tried in update() function on controller is:

• delete rows in pivot table where zone_id is matched
• then insert again

In blade,

<?php
$zone_id = $dataTypeContent->getKey();
$holidays = Holiday::select('id','holiday_name')->get();
$zone_holiday = ZoneHoliday::where('zone_id', $zone_id)->pluck('holiday_id')->toArray();
?>

<div class="form-group">
    @foreach ($holidays as $hol)

     <div class="col-md-4">
         <input type="checkbox" value="{{$hol->id}}" name="holidays[]" {{in_array($hol->id,$zone_holiday)?'checked':''}} >  
         &nbsp;{{ $hol->holiday_name }}&nbsp;
      </div>

    @endforeach
</div>

In controller,

public function _update(Request $request, $id) {
    $holidays = $request->input('holidays');

    if(!empty($holidays))
    { 
       $delete_holidays = ZoneHoliday::where('zone_id', $id)->delete(); //failed at this state

       if($delete_holidays) 
       {
           for($count = 0; $count < count($holidays); $count++)
           {
             $data2 = array(
                  'holiday_id' => $holidays[$count],
                  'zone_id'  => $id,
                );
                $insert_holiday[] = $data2;   
           }
            ZoneHoliday::insert($insert_holiday);
        }
    }
}

The result of this, nothing is deleted in the pivot table, but controller received the request of holiday and id's of zone.

Answer 1

What you seem to be looking for is the sync method that you will also find in the laravel docs https://laravel.com/docs/5.8/eloquent-relationships#updating-many-to-many-relationships

public function _update(Request $request, $id) {
  // I'd expect this to be an array of IDs e.g. [1,2,3]
  $holidays = $request->input('holidays');
  $zone = Zone::find('id', $id);
  $zone->holidays()->sync($holidays);
  ...
}

This will ofcourse only work if you setup your realtions accordingly. https://laravel.com/docs/5.8/eloquent-relationships#many-to-many

It seems you currently have a model for the relation - if it only contains the two IDs I don't think you actually want / need it, as you can query everything relevant via the relations directly. If you have a lot of pivot attributes it might be different.

Answer 2

Use following code

public function _update(Request $request, $zone_id) 
{
     $zone = Zone::find($zone_id);
     $zone->holidays()->sync($request->holidays);
}