Upserting a parent with multiple children

Users Dgraph
1

Hi, I was hoping to upsert a multiple nodes at once. For example, I want to supply a graph that has a parent and two children. The upsert would populate any of those nodes that did not exist, and update the nodes that did exist.

Using the upsert block I was able to pull this off with graphs that had single children in the relationship, but am now stuck when there’s multiple children. I want to write something like so:

upsert {
  query {
    q(func: eq(name, "parent1")) {
      v as uid
      name
      has_child @filter(eq(name, "child1")){
        v2 as uid
      }
      has_child @filter(eq(name, "child2")){
        v3 as uid
      }
    }
  }

  mutation {
    set {
      uid(v) <name> "parent1" .
      uid(v) <has_child> uid(v2) .
      uid(v) <has_child> uid(v3) .
      uid(v2) <name> "child1" .
      uid(v3) <name> "child2" .
    }
  }
}

However specifying multiple <has_child> relationships is forbidden. What would be the most idiomatic way to solve this?

2

It should be successful. What is the error?

BTW, no need to add this. Unless you really wanna change their name.

3

@MichelDiz The error I get is Error: t: : while converting to subgraph: has_child not allowed multiple times in same sub-query.

I’m using dgraph 1.1.1

4

Can you check if the has_child is 1:1 or 1 to many in your schema?
e.g:
has_child: uid . = 1:1
and
has_child: [uid] . = 1:Many

5

@MichelDiz Thanks for responding- in my schema it is one to many:

<has_child>: [uid] .

6

Oh, I just noticed the issue. You have to use an alias when using the same edge multiple times in the same block.

Here is the solution

upsert {
  query {
    q(func: eq(name, "parent1")) {
      v as uid
      name
      has_child @filter(eq(name, "child1")){
        v2 as uid
      }
      has_child2: has_child @filter(eq(name, "child2")){
        v3 as uid
      }
    }
  }

  mutation {
    set {
      uid(v) <name> "parent1" .
      uid(v) <has_child> uid(v2) .
      uid(v) <has_child> uid(v3) .
      uid(v2) <name> "child1" .
      uid(v3) <name> "child2" .
    }
  }
}
7

@MichelDiz Ahh awesome thanks! I actually tried that with the has_child2 AS has_child syntax but I see thats for variablizing and not aliasing. Works great :slight_smile: