How to find nodes without dgraph.type?

Users Dgraph
,
1

I had some bad data when importing using live loader (my fault). I need to delete all of the relations to these empty nodes. The only thing they contain is a uid. They were not specified a dgraph.type or any other properties as I mistyped their blank node in the script.

How can I find nodes that only have a uid and nothing else? I know it will be bad performance, but it will not be a frequent query.

I tried:

query {
  node(func: has(uid)) @filter(NOT has(dgraph.type)) {
    uid
  }
}

But that gives me:

errors… while converting to subgraph: Argument cannot be “uid”

So how else could this be done?

2

There’s no easy way, only this one:

query {
  va1 as var(func: has(pred1))
  va2 as var(func: has(pred2))
  va3 as var(func: has(pred3))
  va4 as var(func: has(pred4))
  va5 as var(func: has(pred5))
  va6 as var(func: has(pred6))
  va7 as var(func: has(pred7))
  
  node(func: uid(va1,va2,va3,va4,va5,va6,va7)) 
    @filter(NOT has(dgraph.type)) {
    uid
  }
}
3

what does pred* mean? Is it just saying has the first predicate, has the second predicate? Where is it getting these predicates from?

4

Not sure if I got your question. This query is an example of a fixed query. The preds have to be manually added to the query. There’s no way, as far as I know, to do it automatically.

As has() func doesn’t support multiple predicates as params or variables with predicates. You have to manually add it.

5

but my nodes don’t have any predicates. They are basically just an empty node with uid only. There are other nodes that have them as children and I need to delete them globally to resolve grpahql errors with missing required fields when it links to these empty nodes.

6

Oh, you wanna find “empty nodes”. From the way you said it, I thought you wanted any nodes with some information. So in your case, you wanna find “dangling empty nodes”.

You can try with reverse

query {
  va1 as var(func: has<(~pred1>))
  va2 asvar(func: has(<~pred2>))
 
  node(func: uid(va1,va2)) @filter(NOT has(dgraph.type)) {
    uid
  }
}

Or query for the parent node and collect only those children who don’t have dgraph.type.

3 Likes
7

This is what I will have to do. Thank you.

After writing the upsert I had to do it this way anyways, because the delete * P O is invalid syntax.

1 Like