'integer', 'mentioned_user_id' => 'integer', 'artwork_id' => 'integer', 'comment_id' => 'integer', 'created_at' => 'datetime', ]; public function actor(): BelongsTo { return $this->belongsTo(User::class, 'user_id'); } public function mentionedUser(): BelongsTo { return $this->belongsTo(User::class, 'mentioned_user_id'); } public function artwork(): BelongsTo { return $this->belongsTo(Artwork::class); } public function comment(): BelongsTo { return $this->belongsTo(ArtworkComment::class, 'comment_id'); } }