related().attach() doesn't check existance of relation (many to many)

[guoyunhe]

I have this code to add new relationship:

post.related('images').attach([imageId]);

I thought that it would check existance before creating new relationship. But it throws error when inserting duplicate images:

  insert into `post_image` (`post_id`, `image_id`) values (14, '27') - Duplicate entry '14-27' for key 'post_image.post_image_post_id_image_id_unique'

Do I have to query existing relationships before adding new ones?

[RomainLanz]

Hey @guoyunhe! 👋🏻

Use sync instead.

post.related('images').sync([imageId], false);

📚 https://docs.adonisjs.com/reference/orm/relations/many-to-many#sync