How do I implement a weighted edge graph using GraphQL?

Question

I'm building a system that analyses sentences and stores the frequency that words follow one another. The idea is that after analysing the following sentences:

what is the time
the time is 4pm

The database would contain:

  [start of sentence]: followed by ("what": 1 time, "the": 1 time)
  "what": followed by............. ("is": 1 time)
  "is": followed by................("the": 1 time, "4pm": 1 time)
  "the": followed by...............("time": 1 time)
  "time": followed by..............([end of sentence]: 1 time, "is": 1 time)
  "4pm": followed by...............([end of sentence]: 1 time)

I could do it with an RDBMS, but it seems a graph database should be a better fit so I'm trying to do it with Dgraph. I've used this schema:

type Word {
  text: String! @id
}
type Transition {
  from: Word 
  to: Word
  count: Int!
}

In Transition, I'm using null values in from and to represent the start- and end-of-sentence markers respectively.

I've managed to write a query to get words that follow the sentence start:

  query GetFirstWords {
    queryTransition(filter: {not: {has: from}}) {
      to {
        text
      }
      count
    }
  }

I've not managed to get the other words though. The most logical thing (to me) based on the above was:

  query GetNextWords {
    queryTransition(filter: {from: {text: {eq: "what"}}}) {
      to {
        text
      }
      count
    }
  }

But that (and most other things I've tried) end up with errors like:

Field 'from' is not defined by type 'TransitionFilter'.

You probably already know I'm a beginner with Dgraph and GraphQL, so it's totally likely the schema I'm using isn't suitable. I tried adding an ID parameter to it also, in case the lack of a non-string ID was the problem, but no joy. I'm also confused that lots of GraphQL examples I see don't look like the Dgraph ones, and also don't work, e.g. nothing works without the queryTransition part, and is there extra schema somewhere where TransitionFilter etc are defined?

How do I implement a weighted edge graph using GraphQL?

0 Answers0