laravel select マルチ 保存方法 多対多テーブル利用

        <select class="form-control select2" multiple="" name="items[]" >
         @foreach ($itemss as $item)
            <option value="{{ $item->id }}">{{ $item->name }}</option>
         @endforeach
        </select>

        --Model--
        TableA
        TableA_TableB
        TableB
        --Controller-
        
        foreach($request->items as $itemId) {
            $table_AB = new TableA_TableB();
            $table_AB->$table_a_id = $table_a->id;
            $table_AB->table_b_id = $itemId;
            $table_AB->save();
        }