如何更新 laravel 中的 pivot 表？

Question

My header question looks so broad. Let me just describe it below.

I have 3 tables the posts , tags , and post_tags . I have use syncWithoutDetaching and so far its working fine. My only issue is when I do updating, it does not do the exact thing I expected.

Lets say I have already existing data(below picture).

And I want to send again another data

"tags":[1,3]

I expect using syncWithoutDetaching it would output these data below

But it returns it results into three like below

---

Someone knows how to achieve this expectation, I think syncWithoutDetaching is not the perfect fit for this.

Answer 1

the behavior that you are after is Sync with detaching. So use sync()

Basicly, when you use sync , giving it "tag":[1,4] will remove existing entries and add the new ones, so only tag id 1 and 4 will still be there

Using syncWithoutDetaching , giving it "tag":[1,4] will add the tag id 1 and 4 on top of what is already in there (without risk of duplication)