Laravel多对多态关系不起作用

Question

hi I'm trying to use many to many polymorphic but somehow it doesnt work I attach my code can you find out what I do wrong?

my migration :

 Schema::create('stickers', function (Blueprint $table) {
        $table->increments('id');

        $table->string('name');
        $table->string('type');

        $table->timestamps();
    });
    Schema::create('stickables', function (Blueprint $table) {

        $table->integer('sticker_id')->nullable();
        $table->integer('stickable_id');
        $table->string('stickable_type');
        $table->primary(['sticker_id', 'stickable_id', 'stickable_type']);

        $table->foreign('sticker_id')
            ->references('id')->on('stickers')
            ->onDelete('cascade');
        $table->timestamps();
    });

and my models

Trip model:

public function stickables()
{
    return $this->morphToMany(Stickable::class, 'stickable');
}

Stickable model:

 public function trips()
{
    return $this->morphedByMany(Trip::class, 'stickable');
}

controller:

public function store(Request $request)
{

    $trip = new Trip();
    $trip->name = $request->name;
    $trip->desc = $request->desc;
    $trip->creator_id = Auth::user()->id;
    $trip->save();

    $tags=$request->tags;
    $trip->stickables()->attach($tags);
    $trip->save();
    return redirect('/trip');
}

Answer 1

Here is how you should define your relationship:

Trip Model:

public function stickers()
{
    return $this->morphToMany(Sticker::class, 'stickable');
}

Sticker Model:

public function trips()
{
    return $this->morphedByMany(Trip::class, 'stickable');
}

You don't need a model for your relationship ( Stickable ).You should create a model for stickers and define your relationship on that.

Stickable can refer to Trip or any other type of model you need to create a relationship with stickers. However in your code you have a stickable method on the Trip model, which does not make sense.

Eloquent Many to Many Polymorphic Relationships