do i need a graph database?

Smart Data for Smarter Business | © 2016 Capsenta | capsenta.com

Do I need a Graph Database?

Juan F. Sequeda, Ph.DCo-FounderCapsenta

1Data/Graph Day Texas – January 14, 2017


• Last year, a talk at Data Day– Client thought they had a graph problem– Evaluated graph databases

• Guess what… – queries were faster in Postgres

• Did they really have a graph problem?


What type of graphs are we talking about?

3


Property Graphs vs RDF Graphs

4

:Bob :Alicefoaf:knows

“Bob Smith”

foaf:name

“Alice Smith”

foaf:name

id1 id2

knowskey value

name Bob Smith

key value

name AliceSmith

key value

since 2005

:g1

2005

:since

http://db-‐engines.com/en/ranking/graph+dbms http://db-‐engines.com/en/ranking/rdf+store

• W3C Standard• Based on Triples• Graph Data Model for the Web (URIs)

• No Standard (Cypher, Titan, etc.)• Key/Values on Nodes and Edges


Flexibility Data Integration Semantics Provenance “Graphy”

QueriesGraph

Visualization

Cold Data

Warm Data



QueriesGraph

Visualization

Cold Data

Warm Data

Cold Data• New Project• New Data• Should I use a Relational DB or a Graph DB?



QueriesGraph

Visualization

Cold Data

Warm Data

Warm Data• Data already exists • Applications consuming existing data• Should I move my relational data to a Graph DB?• Do I keep two copies of my data (relational and graph)?



QueriesGraph

Visualization

Cold Data

Warm Data

Flexibility


Flexible

9

:US_Constitution_1992/section/123

“Excessive bail shall not be required, nor

excessive fines imposed, nor cruel and unusual punishments inflicted.”

:text

:US_Constitution_1992 “United States of America 1789 (rev. 1992)”

:text

:isSectionOf

:Cruelty:hasTopic

“Prohibition of cruel or degrading treatment”

:label

“inhumane treatment”

:keyword


Data and Metadata are One

10


“Excessive bail shall not be required, nor excessive fines imposed, nor cruel and unusual punishments

inflicted.”

:text


:isSectionOf

:Cruelty:hasTopic


:label


:keyword

:text

:Section :Constitution:Topic

:Rights_and_Duties

:Physical_Integrity_Rights

:subClass

:subClass

:subClass

:hasTopic :isSectionOf

:type

:type


Flexibility in RDBMS

11

id attr1 attr2 attr3 attr4 … attrn …

id attribute value

id attr1 val1 attr2 val2 attr3 val3

id valueattr1

id valueattr2

id valueattr3

Copeland and Khoshafian. A decomposition storage model. SIGMOD 1985

Agrawal et al. Storage and Querying of E-‐Commerce Data. VLDB 2001


Query Federation

Virtualize Relational Data as (RDF) Graphs

12

Virtualize Relational Databases as RDF Graphs using R2RMLKeep your legacy data in the RDBMS

Run graph queries over the virtual graph data

Add new data that doesn’t fit into the schema into a separate graph

Federate queries over Virtualized Graph and the Real Graph



QueriesGraph

Visualization

Cold Data

-‐ Graph butdepends on flexibilityneeds

-‐ RDF vs PG?

-‐ RDF if Metadatais Key

Warm Data

-‐ HybridRelational/RDF butdepends on flexibilityneeds

-‐ RDF+R2RML

Data Integration


Graphs are a Common denominator

14

<constitution id=“US_Constitution_1992”><section id="US_Constitution_1992/section/123">

<text>Excessive bail shall ...</text></section><topic>Cruelty</topic>

</constitution>

“Excessive bail shall not be required, nor excessive fines imposed, nor cruel and unusual punishments inflicted.”

id text topic123 Excessive bail

shall… Cruelty



inflicted.”

:text:Cruelty

:hasTopic

XML Text

Tabular


Integration

15



inflicted.”

:text


:isSectionOf

:Cruelty:hasTopic


:label


:keyword

:text

:EighthAmendment_USConstitution :Farmer_vs_Brennan

:lawsApplied

“A prison official’s ‘deliberate indifference’ to a substantial risk of a

serious harm to an inmate violates the Eighth

Amendment”

:holding:sameAs

:Prisons_in_Indiana :LGBT_right

_case_laws

:subject :subject


Integrate Data using Graphs

16


Query Federation

Virtually Integrate Data using Graphs

17



QueriesGraph

Visualization

Cold Data


-‐ RDF vs PG?


-‐ RDF Graphs because of URIs!

-‐ SPARQLhas federation

Warm Data


-‐ RDF+R2RML

-‐ VirtualizeRDBMS as RDF

Semantics


Semantics

19



inflicted.”

:text:Cruelty

:hasTopic


:label


:keyword

:Physical_Integrity_Rights

:subClass

:hasTopic



QueriesGraph

Visualization

Cold Data


-‐ RDF vs PG?




-‐ RDF supports inference with OWL ontologies

Warm Data


-‐ RDF+R2RML


-‐ Limitedinference available over Virtual Relational RDF graphs

Provenance



“Bob Smith”

foaf:name

“Alice Smith”

foaf:name

id1 id2

knowskey value

name Bob Smith

key value

name AliceSmith

Bob Smith knows Alice Smith


“Bob Smith”

foaf:name

“Alice Smith”

foaf:name

id1 id2

knowskey value

name Bob Smith

key value

name AliceSmith

key value

since 2005

:g1

2005

:since

Bob Smith knows Alice Smith since 2005


“Bob Smith”

foaf:name

“Alice Smith”

foaf:name

:s1 2005:since

:Bob :AliceknowsSince2005

“Bob Smith”

foaf:name

“Alice Smith”

foaf:name

foaf:knows

subProperty


id1 id2

knowskey value

name Bob Smith

key value

name AliceSmith

key value

since 2005

Juan said in 2017: Bob Smith knows Alice Smith since 2005


“Bob Smith”

foaf:name

“Alice Smith”

foaf:name

:s1 2005:since

:Juan :Event1:actorInvovled

:stated

2017:createdEvent1

key value

created

2017

id3

key value

name Juan

id1key value

Prop knows

International Semantic Web Conference 2016



QueriesGraph

Visualization

Cold Data


-‐ RDF vs PG?





-‐ PG if statements on edges

-‐ Otherwise RDF vs PG vs RDB?

Warm Data


-‐ RDF+R2RML



-‐ HybridRelational/RDF

“Graphy” Queries


Traversal, Navigation, Reachability

24



inflicted.”

:text


:isSectionOf

:Cruelty:hasTopic


:label


:keyword

:text

:EighthAmendment_USConstitution :Farmer_vs_Brennan

:lawsApplied

“A prison official’s ‘deliberate indifference’ to a substantial risk of a

serious harm to an inmate violates the Eighth

Amendment”

:holding:sameAs

:Prisons_in_Indiana

:LGBT_right_case_laws

:subject :subject

• Conjunctive Query (CQ)• Regular Path Queries (RPQ)

• regular expression over edge labels• Conjunctive Regular Path Query (CRPQ)• Union Conjunctive Regular Path Query (UCRPQ)• Shortest Path• Page Rank• Graph Algorithms …

https://github.com/graphMark/gmark

Bagan et al. gMark: Schema-‐Driven Generation of Graphs and Queries. Journal Transactions on Knowledge and Data Engineering. 2017



QueriesGraph

Visualization

Cold Data


-‐ RDF vs PG?





-‐ PG if statements on edges


-‐ RDF and PG both support

Warm Data


-‐ RDF+R2RML




-‐ VirtualizeRDBMS as RDF and use recursion (?)

-‐ Move to Graph (?)

Graph Visualizations


• Gruff• Linkurious• D3• Tom Sawyer• Keylines• …



QueriesGraph

Visualization

Cold Data


-‐ RDF vs PG?





-‐ PG if statements on edges is sufficient


-‐ RDF and PG both support

-‐ PG seem to have more Graph Viztooling

-‐ RDF is not that behind though

Warm Data


-‐ RDF+R2RML




-‐ VirtualizeRDBMS as RDF and use recursion (?)


-‐ VirtualizeRDBMS as RDF and use Viztools (?)


Conclusion


Takeaway: Tipping Point

28

Relational Database

Graphs

• Flexible• Data Integration• Semantics• Provenance• “Graphy” Queries• Graph Visualizations

Be skeptical!Ask Why?

Do you really need another database?


THANK YOU

Juan Sequeda, Ph.DCo-‐Founder – [email protected]@juansequeda

29

Sequeda J. Integrating Relational Databases with the Semantic Web. IOS Press. 2016http://www.iospress.nl/book/integrating-‐relational-‐databases-‐with-‐the-‐semantic-‐web/

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