Tag Archives: nosql

Feb 28 2012
46 Comments
Java

Batch Importer – Part 1

Data is everywhere… all around us, but sometimes the medium it is stored in can be a problem when analyzing it. Chances are you have a ton of data sitting around in a relational database in your current application… or you have begged, borrowed or scraped to get the data from somewhere and now you want to use Neo4j to find how this data is related.

Michael Hunger wrote a batch importer to load csv data quickly, but for some reason it hasn’t received a lot of love. We’re going to change that today and I’m going to walk you through getting your data out of tables and into nodes and edges.

Let’s clone the project and jump in.
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Feb 21 2012
2 Comments
Gremlin, Neography

Max Flow with Gremlin and Transactions

The maximum flow problem was formulated by T.E. Harris as follows:

Consider a rail network connecting two cities by way of a number of intermediate cities, where each link of the network has a number assigned to it representing its capacity. Assuming a steady state condition, a nd a maximal flow from one given city to the other.

Back in the mid 1950s the US Military had an interest in finding out how much capacity the Soviet railway network had to move cargo from the Western Soviet Union to Eastern Europe. This lead to the Maximum Flow problem and the Ford–Fulkerson algorithm to solve it.
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Feb 13 2012
10 Comments
Cypher, Visualization

Visualizing a Network with Cypher and D3.js

We’ve seen some pretty nice visualizations of nodes and their immediate neighbors, but we want to be able to visualize more. So we’re going to prepare a 200 node network, use Cypher to extract the data we want and visualize it with D3.js.
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Feb 02 2012
3 Comments
Visualization

Graph Visualization and Neo4j – Part Two

If you’re into NoSQL and Graph Databases like Neo4j, then you’ll probably tend to be working on back-end development. If you’re lucky enough to work in a team of specialists, some UX guy will come up with user requirements, hand them off to a UI gal for design, who will then pass it on to a Javascript Ninja to slice it together and they’ll just ask you provide the data and stuff it in a JSON object.

If you’re not so lucky and are working on pet projects by yourself then you’ll have to do it all. So I wanted to give you a little nudge into learning a visualization framework. Since my most popular blog post so far has been Graph Visualization and Neo4j and we’ve already seen one example that you’ll probably want to customize in your projects, we’ll stick with processing.js, and in the future I can do a little intro on D3.js, Unveil.js and maybe something a little crazier like VVVV.js.

So getting started is really easy. We’ll create an html document, add the minified processing javascript library and create a canvas element to put our visualization.

<!DOCTYPE html>
<html>
	<head>
		<title>Hello World - Processing.js</title>
		<script src="processing-1.3.6.min.js"></script>
	</head>
	<body>
		<canvas data-src="helloworld.pjs"></canvas>
	</body>
</html>

All right, let’s create the helloworld.pjs we reference as our canvas data source.
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Jan 30 2012
7 Comments
Gremlin, Neography

Who is the Greatest?

I done wrestled with an alligator, I done tussled with a whale, only last week I murdered a rock, injured a stone, hospitalized a brick. I’m so mean I make medicine sick.

He floats like a butterfly and stings like a bee, but is Muhammad Ali truly the greatest? Greater than the Beatles? Greater than Alexander? Greater than Sliced Bread? Let’s find out.

We begin by requiring neography and creating a function to help us create the greats.

require 'rubygems'
require 'neography'

def create_great(name)
  Neography::Node.create("name" => name)
end

There are a ton of greats out there, but we’ll keep it simple and create just 8 of the greatest greats.
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Jan 18 2012
1 Comment
Heroku, Neography

Neo4j on Heroku – Part Three

This week we learned that leaving the create_graph method accessible to the world was a bad idea. So let’s go ahead and delete that route in Sinatra, and instead create a Rake Task for it.

In Rakefile:

require 'neography/tasks'
require './neoflix.rb'

namespace :neo4j do
  task :create do
    neo = Neography::Rest.new(ENV['NEO4J_URL'] || "http://localhost:7474")
    create_graph(neo)
  end
end

That’s much better. We can create our graph locally with
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