Vertices

Working with vertices is straightforward with Hermes and the functions within hermes.vertex.

create!

hermes.vertex/create! takes an element, and optionally a map of properties, and creates a vertex within the graph.

(def example-1 (v/create!)) 
;;#<PersistStandardTitanVertex v[348]>
(def example-2 (v/create! {:a 1 :b 2})) 
;;#<PersistStandardTitanVertex v[352]>
(v/prop-map example-2)
;;{:id 352, :a 1, :b 2}

get-by-id

hermes.vertex/get-by-id takes an id and retrieves that vertex from the graph.

(def example (v/create!))      
;;#<PersistStandardTitanVertex v[364]>
(v/get-by-id (v/get-id example))
;;#<PersistStandardTitanVertex v[364]>

find-by-kv

hermes.vertex/find-by-kv takes a key and a value and checks indices of that key for the given value. Returns a set of all vertices that match the key/value pair. The indices need to be indexed though (checkout out types and groups for how to set this up).

(v/create! {:indexed-a 1 :name "example 1"})
;;#<PersistStandardTitanVertex v[384]>
(v/create! {:indexed-a 1 :name "example 2"})
;;#<PersistStandardTitanVertex v[412]>
(v/find-by-kv :indexed-a 1)
;;#{#<PersistStandardTitanVertex v[412]> #<PersistStandardTitanVertex v[384]>}

upsert!

hermes.upsert! takes in a key and a map and does a upsert like operation. It takes the key and the value of the key from the map, finds all of the vertices that match the pair, and merges the map into the properties of the returned vertices. hermes.upsert! returns a PersistentHashSet of all the updated vertices.

(v/create! {:age 1 :name "Titan"})
;;#<PersistStandardTitanVertex v[432]>
(v/create! {:age 1 :name "Titan"})
;;#<PersistStandardTitanVertex v[444]>
(v/upsert! :age {:age 1 :type "Project"})
;;#{#<PersistStandardTitanVertex v[432]> #<PersistStandardTitanVertex v[444]>}
(map v/prop-map (v/upsert! :age {:age 1 :type "Project"}))
;;({:id 432, :age 1, :name "Zack", :type "Project"} {:id 444, :age 1, :name "Titan", :type "Project"})