Introduction to Graphs, Apache TinkerPop and Gremlin through DataStax Enterprise (DSE) Graph and DataStax Studio from the Apache Cassandra & DataStax DC Meetup.

1. Gremlin Queries with
DataStax Enterprise Graph
Stephen 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: Paras
label: employs
since: 2015
label: 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
Resources