About this guide

This guide covers

  • How to connect vertices with edges
  • How to delete edges
  • How to work with edge attributes

What version of Titanium does this guide cover?

This guide covers Titanium 1.0.0-beta1.

Working with Edges

Good news everyone! If you understood the section on working with vertices, then you already understand about half of what it takes to work with edges. clojurewerkz.titanium.edges contains analogs for get, keys,id-of, to-map, assoc!, dissoc!, merge!, update!, clear!,refresh,delete!, and find-by-id. All of the previous functions do exactly the same thing for edges as they do for vertices (with the exception that to-map returns a map with an extra :__label__ property). The functions below are unique to clojurewerkz.titanium.edges.

All examples should run with the following namespace declaration and example data.

(ns titanium.intro
  (:require [clojurewerkz.titanium.graph    :as tg]
            [clojurewerkz.titanium.vertices :as tv]
            [clojurewerkz.titanium.edges    :as te]))

(tg/open (System/getProperty "java.io.tmpdir"))            

(def Zack (tg/transact! (tv/create! {:name "Zack"})))
(def Brooke (tg/transact! (tv/create! {:name "Brooke"})))
(def familial-tie (tg/transact! (te/connect! (tv/refresh Zack)
                                             :brother-to 
                                             (tv/refresh Brooke))))

Getting edge label

label-of returns the label of an edge. 

(tg/transact! (te/label-of (te/refresh familial-tie)))
;= :brother-to

Creation

Below are functions for creating edges between vertices.

Simple connect

connect! takes in a vertex, a label, another vertex and, optionally, a map of properties. The function creates an edge that points from the first vertex to the second vertex with the given label and properties. 

(tg/transact! (te/connect! (tv/refresh Zack)
                           :brother-to 
                           (tv/refresh Brooke)))

Upconnect

upconnect! is a rough analog to upsert!. Given the same arguments as connect!, upconnect! checks to see if there are any edges with the given label between the given vertices. If so, it updates the found edges with the new properties. If not, it creates the edge and assigns the given properties to it.

(tg/transact! (tv/upconnect! (tv/refresh Zack)
                             :brother-to 
                             (tv/refresh Brooke)))

Unique upconnect

unique-upconnect! does the same thing as upconnect!, but only returns one edge. If more than one edge is returned, an error is thrown.

(tg/transact! (tv/unique-upconnect! (tv/refresh Zack)
                                    :brother-to 
                                    (tv/refresh Brooke)))

Retrieve all edges

get-all-edges returns all the edges in the graph. Don't hurt yourself.

(tg/transact! (tv/get-all-edges))

What's next

We recommend that you read the following guides in this order:

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Tell Us What You Think!

Please take a moment to tell us what you think about this guide on Twitter or the Titanium mailing list.

Let us know what was unclear or what has not been covered. Reader feedback is key to making the documentation better. If we know people are reading the documentation, we'll be much more inclined to make the documentation that much better. Please speak up!