Mar 21 2018
5 Comments
Cypher, Problems

Neo4j Geospatial Queries

When I was growing up, the Neo Geo was the high end gaming system around. It was however prohibitively expensive for most people… and definitely out of my price range. I grew up in a mobile home park in Union City, CA. Near the old drive in theater now long gone. It was also next to an industrial park in Hayward where a food truck would make the best burritos $3 could buy. A search for the best burritos in Union City would have missed this food truck gem. Geographic boundaries can be a problem when searching for things by specific places. To get around this problem, we tend to use latitude and longitude and then perform a radius or bounding box search. Today I want to present to you a hybrid approach using Neo4j.

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Mar 12 2018
9 Comments
database

Keeping Properties Secret in Neo4j

We’re an open source company with nothing to hide, but some of our customers have things they need to keep close to their chest. Sometimes you don’t want everybody to have access to salary information, or future predictions. Maybe you want to hide Personally identifiable information (PII) or Health Insurance Portability and Accountability Act (HIPPA) data. In Neo4j 3.4 we are introducing more security controls. We are starting with Role based Database wide property key blacklists. That’s a bit of a mouthful but let’s walk through and example to see one of the ways it can be utilized. Imagine you are working in “Area 51” and have to deal with very important information.
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Feb 23 2018
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Java, Problems

Replicants

In the movie Blade Runner, “replicants” are engineered biological copies of humans. They are implanted with memories that aren’t real (to them anyway, they are sometimes the recorded memories of other people) in order to provide a sort of replacement to their emotions. The replicants are meant to work in outer space and are illegal on earth. The ones that manage to get to earth are hunted down by Deckard and other blade runners. In order to determine who is a replicant and who is a “real person” blade runners use a “Voight-Kampff” test that measures respiration, heart rate, blushing and eye movement in response to emotionally provocative questions. Today we are going to turn Neo4j into a blade runner and use it to find and retire replicated identities in our data.
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Jan 26 2018
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Java, Problems

Dynamic Rule Based Decision Trees in Neo4j – Part 2

A couple of weeks ago I showed you how to build a dynamic rule based decision tree in Neo4j. It was pretty simple and used an Expression Evaluator to determine if a set of parameters in an expression was true or false. Based on that answer it decided where to go.

But what if we had more than just true or false? What if we wanted to make our Rule nodes have more than 2 options? Today I am going to show you how to do just that… but please make sure you have read part 1 already.

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Jan 17 2018
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database, Gremlin, Java

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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Jan 14 2018
2 Comments
Java, Problems

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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Dec 13 2017
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Java, Random

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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Dec 13 2017
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Java

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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Nov 21 2017
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Cypher, Problems

Mutual Fund Benchmarks with Neo4j

Just the other day I had a conversation with an Investment Risk Manager about one of the data problems his team was working on and he was wondering if Neo4j could help. Imagine you have about 20,000 mutual funds and etfs and you want to track how they measure up against a benchmark like say the returns of the S&P 500. I’m sorry did I say one? I meant all of them, let’s say 2,000 different benchmarks… and you want to track it every day, for a rolling 5 years period. So that’s 20,000 securities * 2000 benchmarks * 5 years * 252 trading days a year (on average)… or 50 billion data points. That’s a BIG join table if we were using a relational database. How can we efficiently model this in Neo4j?
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Nov 17 2017
5 Comments
Cypher, Problems

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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