Tag Archives: graph

Neptune and Uranus

Last year Microsoft announced “Cosmos DB”, a multi-modal database with graph support. I think multi-modal databases are like swiss army knifes, they can do everything, just not very well. I imagine you would design it to be as good as it can be at its main use case while not losing the ability to do other things. So it’s neither fully optimized for its main thing, nor very good at the other things. Maybe you can do pretty well with two things by making a few compromises, but if you try to do everything…it’s just not going to work out.

Can you imagine John Rambo stalking his enemies with an oversized swiss army knife? Here, let me help with the mental image:
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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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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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Bill of Materials in Neo4j

Where is da BOM? The above question asks, and the obvious answer is right in the middle of your organization. Nestled between Manufacturing, Design, Sales and Supply Chain. But I have a better answer. Your Bill of Materials should be in Neo4j. Today, I’ll show you why.
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Work Order Management with Neo4j

I look terrible in a bikini (take my word for it) but I’d love me a Lamborghini. However, in order to afford nice things, we need to do as the song says and get to work…and we need to manage and prioritize that work somehow. Today, I’m going to show you how to build part of a work order management system with Neo4j.

I’m going to build an evented work order model. So let’s say our Order gets created, then based on what it is, pieces of Work need to happen. This work is performed by some Provider (whether internal or external) and that work can be broken down into Tasks that have dependencies on Events that have occurred. How would this look like in the graph? Glad you asked:
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Building a Boolean Logic Rules Engine in Neo4j

A boolean logic rules engine was the first project I did for Neo4j before I joined the company some 5 years ago. I was working for some start-up at the time but took a week off to play consultant. I had never built a rules engine before, but as far as I know ignorance has never stopped anyone from trying. Neo4j shipped me to the client site, and put me in a room with a projector and a white board where I live coded with an audience of developers staring at me, analyzing every keystroke and cringing at every typo and failed unit test. I forgot what sleep was, but managed to figure it out and I lost all sense of fear after that experience.

The data model chained together fact nodes with criss crossing relationships each chain containing the same path id property we followed until reaching an end node which triggered a rule. There were a few complications along the way and more complexity near the end for ordering and partial matches. The traversal ended up being some 40 lines of the craziest Gremlin code I ever wrote, but it worked. After the proof of concept, the project was rewritten using the Neo4j Java API because at the time only a handful of people could look at a 40 line Gremlin script and not shudder in horror. I think we’re up to two handfuls now.
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Finding Triplets with Neo4j

A user had an interesting Neo4j question on Stack Overflow the other day:

I have two types of nodes in my graph. One type is Testplan and the other is Tag. Testplans are tagged to Tags. I want most common pairs of Tags that share the same Testplans with a Tag having a specific name. I have been able to achieve the most common Tags sharing the same Testplan with one Tag, but getting confused when trying to do it for pairs of Tags.

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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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Building a Twitter Clone with Neo4j – Part Seven

Alright, we’ve had enough back-end work on our Twitter Clone. Let’s switch gears and get to work on the front end. I’ve decided I’m going to use a Java micro framework for my front end, but if your language of choice is Ruby, Python, Go, or whatever, find an alternative library and follow along.

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Neo4j is faster than MySQL in performing recursive query

5mysql

A user on StackOverflow was wondering about the performance between Neo4j and MySQL for performing a recursive query. They started with Neo4j performing the query in 240 seconds. Then an optimized cypher query got them down to 40 seconds. Then I got them down to…
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