Gremlin Queries with

DataStax Enterprise GraphStephen Mallette

@spmallette

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What is a graph?

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● A property graph is a collection of vertices and

edges○ A vertex represents entities/domain objects

○ An edge represents a directional relationship between

two vertices

○ Vertices and edges have labels and properties

label: person

name: Stephen

label: company

name: DataStax

label: person

name: Paraslabel: employs

since: 2015label: employs

since: 2016

label: knows

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What makes graphs

conceptually simple

to understand?

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Graphs are the

foundation of

intelligence

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When are graphs

useful?

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● Graphs are useful when your data

contains many relationships

● The more relationships you have the

more valuable the graph becomes

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How does Apache

TinkerPop support

graph processing?

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Gremlin - Graph Traversal Language

● Gremlin is a language composed of

steps

● Steps are chained together to form a

graph traversal

● The output of a previous step is the

input to the step that follows

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Gremlin - Graph Traversal Language

g.V()

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Gremlin - Graph Traversal Language

g.V()

g.V().has("person","name","Stephen")

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Gremlin - Graph Traversal Language

g.V()

g.V().has("person","name","Stephen")

g.V().has("person","name","Stephen").outE()

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Gremlin - Graph Traversal Language

g.V()

g.V().has("person","name","Stephen")

g.V().has("person","name","Stephen").outE()

g.V().has("person","name","Stephen").outE().groupCount().

by(label())

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Gremlin Language Variants

● Java

● Groovy

● Scala*

● Clojure*

● Python

● .NET

● Javascript**

* Third-party maintained libraries

** Coming soon

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DataStax Enterprise (DSE) Graph● A scale-out graph database purposely built for cloud applications that need

to act on complex and highly connected relationships.

● Supports a property graph model natively inside the DataStax product,

engineered specifically for DataStax Enterprise (Apache Cassandra,

Search, Analytics).

● Part of DSE’s multi-model platform.

● Apache TinkerPop-enabled with support for OLTP

and OLAP workloads

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DataStax Enterprise (DSE) Graph● Not an embedded graph database

● Schema-based

● Connect with Apache TinkerPop drivers or DataStax drivers

○ Both protocols support Gremlin scripts and bytecode

● DataStax drivers provide additional features over Apache TinkerPop drivers:

○ Cluster awareness/discovery

○ Load balancing

○ Retry policies

○ Cluster metadata

○ Batched requests

○ Advanced security/logging options

○ Native support for Geo types

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DataStax Studio

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KillrVideo

KillrVideo is an open source reference application for developers learning how to

build solutions with Apache Cassandra and DataStax Enterprise.

https://killrvideo.github.io/

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Live Demo

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What's next?

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● Apache TinkerPop Website○ http://tinkerpop.apache.org/

● The Gremlin Compendium○ http://www.doanduyhai.com/blog/?p=13460

● Graph Databases, Gremlin and TinkerPop○ http://kelvinlawrence.net/book/Gremlin-Graph-Guide.html

● DSE Graph○ https://www.datastax.com/products/datastax-enterprise-graph

● DataStax Studio○ https://www.datastax.com/products/datastax-studio-and-development-tools

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