Tag Archives: nosql

Building a Twitter Clone with Neo4j – Part Four

We left off last time having just added the ability to follow people, see who we’ve followed and has followed us, block and unblock people and finally see whom we have put on our naughty list of blocked users. So we have a social network where people can create relationships, but they have nothing to say because we haven’t implemented that yet!
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Building a Twitter Clone with Neo4j – Part One

Would you believe there is no shortage of Twitter Clone example applications…maybe because they are easy to replicate (ba dum tss, I’ll be here all week.) The earliest one I remember was written by Salvatore Sanfilippo creator of Redis.
It’s a pretty good read, where he explains the basics of Redis (a Key Value store on steroids) and how to model a social network in it. One of the interesting bits to me is how the status updates (tweets) are handled.
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Searching for objects using multiple dimensions

Lets take a look at a scenario where you are trying to search for things by their attributes, not their description. They can be users, documents, or any object that could be described by discrete values in multiple dimensions. What does that mean exactly? Well, let me give you an example: searching for a dog. My family includes 2 four legged furry creatures named Tyler and Ronnie. They are my half lab, half golden retrievers. Dogs come in all shapes and sizes, from teacup breeds with adult weights around 5 lbs, to giant Mastiff breeds over 150 lbs. But most people don’t care exactly how much a dog weights, only their general size.


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Property Level Security with Neo4j Enterprise

security-patrol-guard

In Neo4j 3.1 Enterprise edition, we introduced the first wave of security features that are coming down the pipeline. Now you can start off with Administrators, Architects, Publishers and Readers as built in default groups. You can read about their capabilities in the docs.

If you’ve been paying attention, you know Neo4j thrives under it’s dynamic customizability. The developers decided to let us build our own custom Roles and limit their capabilities to a set of Stored Procedures. With this, we can build any kind of access control we want, but let’s go for the jugular and let’s see how we can build property level security for Neo4j.
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Our own Multi-Model Database – Part 1

shittydb

I may be remembering this wrong, but I think it was Henry Rollins who once asked, “What came first, the shitty Multi-Model Databases or the Drugs?” His confusion was over whether:

A) there were a bunch of developers dicking around with their Mac laptops and they wrote a shitty database, put it on github, posted on hacker news, and then other developers who were on drugs started using it or…

B) there were a bunch of developers on ketamine and ecstasy and somebody said lets write a shitty database

I think “A” is what probably happens and how we end up with over 300 databases on DB Engines. But what about “B” ? Well I don’t have any good stuff lying around, but I did hurt my foot the other day and the doctors gave me some Tramadol, so lets down some of that and see what happens.
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News Feeds

Ron Burgundy Gets Hungry

Ron Burgundy (in Anchorman) gets Hungry

The “News Feed” is a core feature of social networks like Twitter, Facebook, or Vine (RIP). Let’s take a look at how we could model and implement this in Neo4j. Our social network needs Users (otherwise it would be kinda empty) that FOLLOW each other (otherwise it would not be very social). Those users need to POST some Messages (otherwise it would be boring). Here is our first attempt at a model (using Arrows):
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Catalogs and Hierarchies

street-samurai-catalog-large

When I was younger, friends and I would play a role playing game called “Shadowrun“. The game draws elements from science fiction, crime dramas, and magic and blends them all together to make a fun mess. You could be a Dwarf Shaman, an Elf Decker, a Human Rigger, an Orc Adept, a Troll Street Samurai or whatever combination your heart desired. Choosing a gender, race and archetype was just the beginning a more important question: “What is your character going to wear and take on missions?”
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Custom Importers

imports

When it comes to getting data into Neo4j, you have a ton of options. You can use LOAD CSV from Cypher, you can use the Import Tool, you can use the JDBC connector in APOC, and possibly a few more options I’m forgetting. Some of these require the data to be in a specific format, others that you write a little custom cypher. These work very well most of the time, but sometimes you run into data in weird shapes and coming in from vendors who aren’t willing to change just for you. What do you do in that case? Well, you write a custom importer. I’m going to show you how by importing the Cities database from MaxMind.
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Flight Search with the Neo4j Traversal API

Screen Shot 2015-08-30 at 2.21.07 AM

Before Cypher came along, if you wanted to describe a graph traversal in Neo4j you would use the Traversal Framework Java API. The Traversal API is one of the many hidden gems of Neo4j and today we are going to take a closer look at it. Traversing a graph is about going on a journey. All journeys have a starting point (or points) so that’s the first thing we have to do, figure out where in the graph we begin. It can be a single node, or multiple ones, but they will go on the journey following the same rules, so its easier if it’s just one node or nodes of the same “type”.
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Using the Testing Harness for Neo4j Extensions

harness

I’ve been creating both unit tests and integration tests for Neo4j Unmanaged Extensions for far too long. The Neo4j Testing Harness was introduced in version 2.1.6 to simplify our lives and just do integration tests. Let’s try it on and see just how awesome we look. First thing we need to do is add the dependency to our project:
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