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Exploring Graphs with Elixir
book

Exploring Graphs with Elixir

by Tony Hammond
November 2022
Intermediate to advanced content levelIntermediate to advanced
294 pages
5h 58m
English
Pragmatic Bookshelf
Content preview from Exploring Graphs with Elixir

Reaching Back to the ARPANET

We’re going to revisit another graph we’ve seen before, the ARPANET, and look at some additional DQL features: inverses, paths, and recursion. So, let’s set up a Dgraph schema for this.

We start by clearing out the graph service of schemas and data:

 iex>​​ ​​graph_delete
 ""

We can now read our Dgraph schema from the graph store:

 iex>​​ ​​IO.puts​​ ​​(arpa70_schema​​ ​​=​​ ​​read_graph​​ ​​"schemas/arpa70.schema"​​).data
 name: string @index(term) .
 type: string @index(term) .
 
 H_LINK: [uid] @reverse .
 N_LINK: [uid] .
 
 type Host {
  name
  type
  <~H_LINK>
 }
 
 type Node {
  name
  type
  N_LINK
 }
 
 :ok

No surprise here, apart from the @reverse directive set on the H_LINK predicate. Also, note the ...

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Publisher Resources

ISBN: 9798888650059Errata Page