How to "upsert" an array/nested field when issuing update mutation in Graphcool / GraphQL?

Question

I have a Post type than has a tag field which can be associated with many Tag entries (man-to-many relationship). The issue I am running into is when updating a Post - I need to both create and associate new Tag's for tags that do not yet exist, while preserving the existing Post->Tag relationships. Basically, what I am looking for is something akin to an upsert when issuing a mutation update on a nested one-to-many field.

Here is my schema:

type Post @model {
  createdAt: DateTime!
  createdBy: User @relation(name: "PostsByUser")
  description: String @defaultValue(value: "''")
  id: ID! @isUnique
  tags: [Tag!]! @relation(name: "TagsOfPost")
  ...
}

type Tag @model {
  id: ID! @isUnique
  tag: String!
  createdBy: User @relation(name: "TagsByUser")
  createdAt: DateTime!
  posts: [Post!]! @relation(name: "TagsOfPost")
}

This mutation works to update a Post and add new tags, but overwrite all of the existing values in the Post's tag field:

mutation updatePost(
  $id: ID!
  $createdById: ID!
  $timestamp: DateTime!
  $description: String
  $tags: [PosttagsTag!]!
) {
  updatePost(
    id: $id
    createdById: $createdById
    timestamp: $timestamp
    description: $description
    tags: $tags
  ) {
    id
    timestamp
    description
    tags {
      id
      tag
    }
    createdBy {
      id
      username
    }
  }
}

I came across this post by @marktani but it's not clear how to implement the combined method he outlines:

Combined You can also use tags and tagsIds in the same mutation, this would connect the new Tutorial node to all the tags in tagsIds and connect it to the new tags in tags. This is what you want to do if you want to only allow tags with a unique text, so for a new Tutorial, there will likely be some tags that already exists, and some that need to be created.

Is it currently impossible to do this with one mutation? Would a second mutation be required after updating the post with new tags to re-establish the associations between the Post and existing Tag ids, i.e., having to repeatedly call addToTagsOfPost(tagsTagId: ID! postsPostId: ID!)? Thanks!

score 1 · Accepted Answer · answered Nov 20 '17 at 17:41

Ok, so there is currently a Graphcool bug where passing in both tags and tagsIds to the mutation will create and associate newly created Tags but will not add the tagsIds associations to existing Tags. I posted an issue on Graphcool's GitHub repo and they have acknowledged it - https://github.com/graphcool/framework/issues/1288

How to "upsert" an array/nested field when issuing update mutation in Graphcool / GraphQL?

1 Answers1