嗨，这是我的代码，但我收到这个错误：

SQLSTATE[42000]: Syntax error or access violation: 1068 Multiple primary key defined (SQL: alter table `wishlists` add primary key (`userId`, `productId`))

代码：

public function up()
    {
        Schema::create('wishlists', function (Blueprint $table) {
            $table->id();
//            Foreign key for Users table
            $table->foreignId('userId');
            $table->foreign('userId')->references('id')->on('users')->onDelete('cascade');

//            Foreign key for Products table
            $table->foreignId('productId');
            $table->foreign('productId')->references('id')->on('products')->onDelete('cascade');

            $table->primary(['userId', 'productId']);

            $table->timestamps();
        });
    }

谢谢
4.我一直在找它，但什么也没找到