CODEWITHSUNDEEP
laraveleloquentrelationshipone-to-manylaravel-blade
LowLevel
LowLevel

Reputation: 1095

Eloquent: How to sync in one to many relations without deleting anything (FK is nullable)?

A branch may have zero(*) or only one holiday plan. A holiday plan may be "linked" (attached) to zero or many branches.

(*) this is very important: it is a Foreign Key which may be null

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Model

Here is my Branch Model:

class Branch extends Model
{
    protected $table = 'branch';
    protected $fillable = ['name', 'holiday_plan_id'];
    public $timestamps = false;

    public function holidayPlan()
    {
        return $this->hasOne('App\HolidayPlan', 'id', 'holiday_plan_id');
    }
}

And here is my HolidayPlan Model:

class HolidayPlan extends Model
{
    protected $table = 'holiday_plan';
    protected $fillable = ['name'];
    public $timestamps = false;

    public function branches()
    {
        return $this->hasMany('App\Branch', 'holiday_plan_id', 'id');
    }
}

View

Now I want to link/unlink a holiday plan to different branches

$branches = Branch::all();
$plan = HolidayPlan::find(1);

@foreach($branches as $branch)
<label>
    <input type="checkbox" name="branch[]"
        value="{{ $branch->id }}"{{ ($branch->holiday_plan_id == $plan->id) ? ' checked' : '' }}>
    {{ $branch->name }}
</label>
@endforeach

Controller

public function linkBranches($planId, Request $request) // post
{
    $plan = HolidayPlan::where('id', $planId)->first();
    $branches = Branch::findMany($request->input('branch'));
    //
    $this->solution1($plan, $branches); // see next
    //
    return redirect()->back();
}

Possible solutions (not working)

private function solution1(HolidayPlan $plan, $branches)
{
    $plan->branches()->sync($branches); // Not working because this function is for Many-to-Many relations
}

private function solution2(HolidayPlan $plan, $branches)
{
    $plan->branches()->delete(); // This will delete my branches, which is not what I want to do, of course
    $plan->branches()->saveMany($branches);
}

private function solution3(HolidayPlan $plan, $branches)
{
    foreach($plan->branches as $branch) {
        $branch->holiday_plan_id = null;
        $branch->save();
    }
    $plan->branches()->saveMany($branches); // Not working; I don't know why: strange behavior. Maybe because of locks; I'm not sure. One time it detaches all branches, and only next time it attaches them again.
}

Finally

Actually, a raw SQL would be:

UPDATE branch SET holiday_plan_id = NULL WHERE holiday_plan_id = 1;
UPDATE branch SET holiday_plan_id = 1 WHERE branch.id IN (2, 5, 7)/* for example */;

But how to do this using Eloquent functions and relations (without raw sql)?

Edit

I've edited my Branch model relationship, however solution3 still doesn't work (when I try to add an already existing holiday_plan_id, it doesn't add it = it becomes null):

public function holidayPlan()
{
    return $this->belongsTo('App\HolidayPlan', 'holiday_plan_id');
}

Upvotes: 3

Views: 2434

Answers (1)

LowLevel
LowLevel

Reputation: 1095

Temporary Solution:

public function solution4(HolidayPlan $plan, $inputBranches)
{
    $oldLinks = $plan->branches;
    $plan->branches()->saveMany($inputBranches);
    foreach ($oldLinks as $oldLink) {
        if (! $inputBranches->contains($oldLink)) {
            $oldLink->holiday_plan_id = null;
            $oldLink->save();
        }
    }
}

Upvotes: 3

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