We’re overhauling Dgraph’s docs to make them clearer and more approachable. If
you notice any issues during this transition or have suggestions, please
let us know.
You can perform deep mutations at multiple levels. Deep mutations don’t alter
linked objects, but they can add deeply nested new objects or link to existing
objects. To update an existing nested object, use the update mutation for its
type.
We use the following schema to demonstrate some examples.
type Author {
id: ID!
name: String! @search(by: [hash])
dob: DateTime
posts: [Post]
}
type Post {
postID: ID!
title: String! @search(by: [term, fulltext])
text: String @search(by: [fulltext, term])
datePublished: DateTime
}
Example: Adding deeply nested post with new author mutation using variables
mutation addAuthorWithPost($author: addAuthorInput!) {
addAuthor(input: [$author]) {
author {
id
name
posts {
title
text
}
}
}
}
Variables:
{
"author": {
"name": "A.N. Author",
"dob": "2000-01-01",
"posts": [
{
"title": "New post",
"text": "A really new post"
}
]
}
}
Example: Update mutation on deeply nested post and link to an existing author using variables
The following example assumes that the post with the postID of 0x456
already
exists, and isn’t currently nested under the author having the id of 0x123
.
This syntax doesn’t remove any other existing posts, it just adds the existing
post to any that may already be nested.
mutation updateAuthorWithExistingPost($patch: UpdateAuthorInput!) {
updateAuthor(input: $patch) {
author {
id
posts {
title
text
}
}
}
}
Variables:
{
"patch": {
"filter": {
"id": ["0x123"]
},
"set": {
"posts": [
{
"postID": "0x456"
}
]
}
}
}
This example query can’t modify the existing post’s title or text. To modify the
post’s title or text, use the updatePost
mutation either alongside the this
mutation, or as a separate transaction.