Dojo : Test Driven Development with graph databases (En anglais) 05/10/17 - Sophia Antipolis

1. Test driven development with
graph databases
@SandorDargo
05/10/2017, Soiree du Test Logiciel
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2. _Father of one
_Developer at Amadeus
_Blogger – http://sandordargo.com
_Amateur of graph databases
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Who am I?

3. _Not a store of excel charts
_Not a data visualization tool
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What is not a graph database?

4. _Type of NoSQL database
_Based on the concepts introduced by Leonhard Euler
_Collections of nodes and relationships
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What is a graph(-oriented) database?

5. _Graph = Nodes + Relationships
_Property Graph = Graph + key-value
attributes/properties
_Labelled Property Graph = Property Graph + Tags/Labels
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Labelled Property Graph Data Model

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A sample graph about wines

7. _Topologies
_Social data
_Page ranking
_Analyse highly connected data (Panama papers)
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When to use a graph (i.e. advantages of a graph)?
“If you can whiteboard it, you can graph it”

8. _Graph database with three different node types
• Wine regions (e.g. Provence)
• Wine subregions (e.g. Bandol)
• Grapes (e.g. Mourvedre)
_Develop services to retrieve the nodes by name and the
related nodes
_Use Java or Python (Java 8 tonight)
_Start code for Java at:
https://github.com/sandordargo/neo-wine-
services/tree/starting-code
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Code Kata

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Creating test data with Cypher
CREATE (eger:WineRegion {name:'Eger'})-[:CONTAINS]
->(eger_subregion:WineSubRegion {name:'Eger'}),
(eger)-[:CONTAINS]->(matra:WineSubRegion {name:'Mátra'}),
(eger)-[:CONTAINS]->(bukk:WineSubRegion {name:'Bükk'}),
(eger_subregion)<-[:GROWS_AT]-(merlot:Grape {name:'Merlot'}),
(eger_subregion)<-[:GROWS_AT]-(pinot_noir:Grape {name:'Pinot Noir'}),
(eger_subregion)<-[:GROWS_AT]-(cabernet_franc:Grape {name:'Cabernet Franc'})

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Simple query with Cypher
MATCH (eger:WineRegion {name:'Eger'})-
[relationship:CONTAINS] ->
(subregion:WineSubRegion)
RETURN eger, relationship, subregion

11. _Ideal when a relationship is OPTIONAL
_Will use null for missing part of a pattern
_Example:
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OPTIONAL MATCH
MATCH (wr:WineRegion)-[:CONTAINS]→
(wsr:WineSubRegion {name:{subregionName}})
OPTIONAL MATCH (wsr)<-[:GROWS_AT]-(grape:Grape)
RETURN wr, wsr, grape

12. Thank you!
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