java | Max De Marzi

Jan 14 2018

Dynamic Rule Based Decision Trees in Neo4j

A few posts ago I showed you how to build a Boolean Logic Rules Engine in Neo4j. What I like about it is that we’ve pre-calculated all our potential paths, so it’s just a matter of matching up our facts to the paths to get to the rule and we’re done. But today I am going to show you a different approach where we are going to have to calculate what is true as we go along a decision tree to see which answer we get to.

Yes, it will be a bit slower than the first approach, but we avoid pre-calculation. It also makes things a bit more dynamic, as we can change the decision tree variables on the fly. The idea is to merge code and data into one, to gain the benefit of agility.

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Tagged decision tree, decision trees, decisions, graph, graph database, graph databases, java, neo4j, network, nosql, software, trees

Dec 13 2017

Adding gRPC to Neo4j

You are probably sick of me saying it, but one of the things I love about Neo4j is that you can customize it any way you want. Extensions, stored procedures, plugins, custom indexes, custom apis, etc. If you want to do it, then you can do it with Neo4j.

So the other day I was like what about this gRPC thing? Many companies standardize their backend using RESTful APIs, others are trying out GraphQL, and some are using gRPC. Neo4j doesn’t support gRPC out of the box, partially because we have our own custom binary protocol “Bolt”, but we can add a rudimentary version of gRPC support quite easily.
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Tagged graph database, grpc, java, neo4j, network, nosql, performance, software, technology

Dec 13 2017

Stored Procedure to Import Data

A while back I showed you how to write an extension to import the MaxMind city data set. Today is just a repeat of that exercise but instead of using an extension, we will use a stored procedure.

The documentation spells out how to write your own procedures in Chapter 6 so I’m not going to go over that again, but I do want to point out a few things.
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Tagged github, graph, graph database, java, neo4j, network, performance, relationship graph, software, technology

May 24 2017

9 Comments

Java, Problems

Flight Search with Neo4j

I think I am going to take the opportunity to explain why I love graphs in this blog post. I’m going to try to explain why looking at problems from the graph point of view opens you up to creative solutions and makes back-end development fun again. The context of our post is flight search, but our true mission is to figure out how to traverse a graph quickly and efficiently so we can apply our knowledge to other problems.

A long while back, I showed you different ways to model airline flight data. When it comes to modeling in graphs, the lesson to take away is that there is no right way. The optimal model is heavily dependent on the queries you want to ask. Just to prove the point, I’m going to show you yet another way to model the airline flight data that is truly optimized for flight search. If you recall, our last model looked like:
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Tagged graph, graph database, graph search, java, neo4j, network, nosql, performance, relationship graph, search, software, technology

May 03 2017

1 Comment

Java

Building a Twitter Clone with Neo4j – Part Eight

In our last post we started the front end of our Twitter Clone application and managed to register and login a user. Now we need to build the actual functionality of our application. We’re going to need a screen to display the timeline of the logged in user. A screen to display a single users posts, and a screen to display the followers of a user and the users being followed. All of these should fit within the same main template, so maybe we can start with that.

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Tagged github, graph database, graph databases, java, neo4j, network, nosql, performance, relationship graph, social network, technology

Apr 19 2017

2 Comments

Java

Building a Twitter Clone with Neo4j – Part Six

We are getting close to wrapping up the back-end API for our Twitter clone, so thank you for sticking with this awfully long series since the beginning. One of the big community features of Twitter is the Trending Hashtags. It lets users know what is being talked about even if the people a user follows aren’t talking about it. It’s kind of weird in that way since part of the point of Twitter is following just a few hundred or thousand people to reduce the noise, and here we are bringing noise back in to our feed. Regardless, this is actually pretty easy to implement, so let’s have a crack at it.
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Tagged graph database, graph databases, java, neo4j, network, social network, software, technology

Apr 10 2017

1 Comment

Java

Building a Twitter Clone with Neo4j – Part Five

In part four, we continued cloning Twitter by adding hashtag and mentions functionality. Then we went beyond it by adding the ability to edit a post. So we have a social network where people can follow each other and post stuff. Today we’re adding the ability to say a user likes a post, reposts a post and the most important query of all, being finally able to see our feed or timeline.
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Tagged graph database, graph databases, java, neo4j, network, social network, software, technology

Apr 05 2017

4 Comments

Java, Problems

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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Tagged graph database, graph databases, java, neo4j, nosql, relationship graph, social network, software, technology

Apr 03 2017

2 Comments

Java, Problems

Building a Twitter Clone with Neo4j – Part Two

One of the aspects of my job that I love is the week long proof of concept bootcamps. What it entail is me (or one of my team members) coming onsite to work with your team to build out a POC in just one week. They all vary some what, but I try to stick to a formula that works for me. I spend the first day with the whole team ironing out the Model. This is the trickiest part to get right, because if the model is right, the queries will fall right into place. If the model has to be changed significantly on day 3 let’s say, then a ton of work has to be redone or at least greatly modified. The goal of the end of day one is to have something that looks like the following:
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Tagged graph database, java, neo4j, network, performance, relationship graph, social network, software, technology

Mar 30 2017

6 Comments

Cypher, Problems

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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Tagged graph database, java, neo4j, network, nosql, performance, relationship graph, social network, software, technology

Max De Marzi

Graphs, Graphs, and nothing but the Graphs

Tag Archives: java

Dynamic Rule Based Decision Trees in Neo4j

Adding gRPC to Neo4j

Stored Procedure to Import Data

Flight Search with Neo4j