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Introduction to graph databases

Kickoff research project

TU-Ilmenau 11/2011

Henning Rauch

Henning@RauchEntwicklung.biz

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Agenda

● Introduction● Graph databases● Pros● Cons● Use cases● Sones GraphDB

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Introduction – /me

● Studied computer science at TU-Ilmenau● 02/2009 – 11/2010 sones core developer of the

sones GraphDB● GraphQL● Type-Management

● 11/2010 – 11/2011 sones Head of R&D● Design of v2 ● Refactoring of v1 → v2 (de-facto rewrite)

● 11/2011 – now NoSQL freelancer & visiting lecturer

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Introduction – Current situation

● Data-intensive, complex and distributed applications● Semantic web● Recommendation systems● Social networks

● Similarities● Strong connected data in large amounts● Complex structures● Continuous growth in data volume● Mix of structured and non-structured (schema-less) data

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Introduction – Example

http://www.facebook.com/press/info.php?statistics

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Introduction – Challenges

● Recursive connected information as a new design goal

● Simple management of structured, semi-structured and unstructured data

● Replication● Versioning● Efficient partitioning of data● Graph oriented operations

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Graph databases – Data model

● Graph G(V,E)● V – Vertices● E – Edges

Vertex0

Vertex1

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Graph databases – Data model

Jena Berlin

Stuttgart

383 km 633 km

260 km

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Graph databases – Property graph

● Extension of the graph data model● Additional properties on vertices and edges● The properties are key/value pairs (Age:23)● Keys are specified by the schema of the vertex type

Name: AliceID: 0

Age: 23

Name: BobID: 1

Age: 42

CommunicatesWithEncrypted : trueMethod : RSA

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Graph databases – Property graph

Name: AliceID: 0

Age: 23

Name: BobID: 1

Age: 42

CommunicatesWithEncrypted: trueMethod: RSA

Name: CarolID: 3

Age: 18

Name: TU Ilmenau

Name: Uni StuttgartStudiesIn

Since: 2007

StudiesIn

Since: 2004

Relat

iveO

f

Degre

e: S

ister

Comm

unicatesWith

Encrypted: false

Stu

die

sIn

Sin

ce:

201

0

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Graph databases – Definition

A graph database is a database that uses graph structures with nodes, edges, and properties to represent and store information. General graph

databases that can store any graph are distinct from specialized graph databases such as triplestores

and network databases.

http://en.wikipedia.org/wiki/Graph_database

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Pros – Data model

● Explicit data model● Direct mapping of real world network

structures

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Pros – Efficient graph traversal

● The most important operation of graph databases

● Recursive search for vertices/edges with certain properties

● Finding paths in graphs● GraphDB is able to do ~80M vertex-

traversals per second

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Pros – Index-free adjacency

● Relations (edges) are directly modeled on the vertex → no need for an additional mapping

● No need for a global index for relations● Data locality → adjacent vertices can be

persisted "close together" (efficient storage)● → The vertex-traversal performance is

independent from the size of the graph

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Cons

● In general the import is slower than in RDBMS

● Relatively new technology● Lack of standards

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Use cases

● Rating of websites in search engines – Page rank

● Who knows-who in social networks – Shortest path

● Recommendation systems – Bipartite matching

● ...

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Sones GraphDB – Overview

● http://www.sones.com● Object-oriented graph database● Property-Hypergraph data model● Written in C# (97%)● C# embedded/remote API● GraphQL● Non-persistent OSE and proprietary persistent

GraphFS

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Sones GraphDB – Architecture

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Sones GraphDB – Architecture

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Sones GraphDB – GraphQL

// define Vertex Type

CREATE VERTEX User

ADD ATTRIBUTES (String Name, SET<User> Friends)

INDICES (Name)

// add vertices Alice and Bob

INSERT INTO User VALUES (Name = "Alice", Age = 23)

INSERT INTO User VALUES (Name = "Bob", Age = 42)

// add edges between Alice and Bob

LINK User(Name = ‘Alice') VIA Friends TO User(Name = ‘Bob')

LINK User(Name = ‘Bob') VIA Friends TO User(Name = ‘Alice‘)

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Sones GraphDB – HowTo run it

● Windows: Install Visual Studio (professional and higher) or MonoDevelop

● Linux: Install mono-complete and MonoDevelop● Download the source from

https://github.com/cosh/sones● Open the „CoreDeveloper.sln“● Have phun

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Sones GraphDB – Documentation

● Blog: http://developers.sones.de/

● Wiki: http://developers.sones.de/wiki/doku.php

● Forum: http://forum.sones.de/

● BugTracking: http://jira.sones.de/

● The fastest way to information: /me :)

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Graph visualization

● http://gephi.org/screenshots/

● http://mbostock.github.com/d3/

● http://www.fluidops.net/information-workbench/