Schema validation and evolution for PGs Eugenia Oshurko (ENS Lyon) - - PowerPoint PPT Presentation

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Schema validation and evolution for PGs Eugenia Oshurko (ENS Lyon) - - PowerPoint PPT Presentation

Oct 13, 2023 221 likes •341 views

Schema validation and evolution for PGs Eugenia Oshurko (ENS Lyon) 7 March 2019 Main ideas Schema as a PG Schema validation via graph homomorphisms Schema nodes define node types Schema relations define relations allowed between

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Schema validation and evolution for PGs

Eugenia Oshurko (ENS Lyon) 7 March 2019

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Main ideas

  • Schema as a PG
  • Schema validation via graph homomorphisms
  • Schema nodes define node types
  • Schema relations define relations allowed between types
  • Properties on schema elements define sets of allowed properties
  • Schema/instance homomorphism allows to use existing tools

from the graph transformation community

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Update semantics

  • Sesqui-pushout (SqPO) rewriting approach
  • Rewriting given a rule and a matching of its left-hand side
  • Two phases
  • restrictive update: delete node/edge/property + clone node
  • expansive update: add node/edge/property + merge nodes

L P R G G− G+

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Schema/instance coupled updates

Prescriptive updates

  • Deletion of schema elements can be propagated to data
  • We can clone schema nodes (split concepts) clone of data

nodes Descriptive updates

  • Creation of data elements can be propagated to schema
  • We can merge nodes of different types merge of schema

concepts Result: instance respects schema at all times

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Prescriptive updates: example

L

Message imageFile: STRING type: {post, comment}

P

Post imageFile: STRING type: post Comment type: comment

S

Person Message

G

n1

firstName: Bryn lastName: Davies

n2

imageFile: photo33711.jpg creationDate: 2010-10-16 browserUsed: Firefox type: post

n3

firstName: Jose lastName: Alonso

n8

creationDate: 2010-10-30 browserUsed: {Firefox, Safari }

n5

firstName: Jane lastName: Murray

n6

creationDate: 2010-10-30 browserUsed: Safari type: comment LIKES K N O W S K N O W S LIKES HAS CREATOR H A S C R E A T O R HAS CREATOR REPLY OF

m h l−

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Prescriptive updates: example

L

Message imageFile: STRING type: {post, comment}

P

Post imageFile: STRING type: post Comment type: comment

S

Person Message

G

n1

firstName: Bryn lastName: Davies

n2

imageFile: photo33711.jpg creationDate: 2010-10-16 browserUsed: Firefox type: post

n3

firstName: Jose lastName: Alonso

n8

creationDate: 2010-10-30 browserUsed: {Firefox, Safari }

n5

firstName: Jane lastName: Murray

n6

creationDate: 2010-10-30 browserUsed: Safari type: comment LIKES K N O W S K N O W S LIKES HAS CREATOR H A S C R E A T O R HAS CREATOR REPLY OF

m h l−

Person

firstName: STRING lastName: STRING gender: STRING birthday: DATE

... Post

imageFile: STRING? creationDate: STRING browserUsed: STRING

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creationDate: STRING browserUsed: STRING

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KNOWS HAS CREATOR H A S C R E A T O R LIKES LIKES R E P L Y O F R E P L Y O F

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Prescriptive updates: example

L

Message imageFile: STRING type: {post, comment}

P

Post imageFile: STRING type: post Comment type: comment

S

Person Message

G

n1

firstName: Bryn lastName: Davies

n2

imageFile: photo33711.jpg creationDate: 2010-10-16 browserUsed: Firefox type: post

n3

firstName: Jose lastName: Alonso

n8

creationDate: 2010-10-30 browserUsed: {Firefox, Safari }

n5

firstName: Jane lastName: Murray

n6

creationDate: 2010-10-30 browserUsed: Safari type: comment LIKES K N O W S K N O W S LIKES HAS CREATOR H A S C R E A T O R HAS CREATOR REPLY OF

m h l−

Person

firstName: STRING lastName: STRING gender: STRING birthday: DATE

... Post

imageFile: STRING? creationDate: STRING browserUsed: STRING

... Comment

creationDate: STRING browserUsed: STRING

...

KNOWS HAS CREATOR H A S C R E A T O R LIKES LIKES R E P L Y O F R E P L Y O F

n1

firstName: Bryn lastName: Davies

n2

imageFile: photo33711.jpg creationDate: 2010-10-16 browserUsed: Firefox type: post

n3

firstName: Jose lastName: Alonso

n8

creationDate: 2010-10-30 browserUsed: {Firefox, Safari }

n9

creationDate: 2010-10-30 browserUsed: {Firefox, Safari }

n5

firstName: Jane lastName: Murray

n6

creationDate: 2010-10-30 browserUsed: Safari type: comment LIKES K N O W S K N O W S LIKES LIKES HAS CREATOR HAS CREATOR H A S C R E A T O R HAS CREATOR REPLY OF REPLY OF

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Descriptive updates: example

P

a b

G

n1

firstName: Bryn lastName: Davies

n2

imageFile: photo33711.jpg creationDate: 2010-10-16 browserUsed: Firefox

n3

firstName: Jose lastName: Alonso

n4

creationDate: 2010-10-30 browserUsed: Firefox

n5

firstName: Jane lastName: Murray

n6

creationDate: 2010-10-30 browserUsed: Safari

n7

creationDate: 2010-10-30 browserUsed: Safari LIKES K N O W S K N O W S LIKES HAS CREATOR H A S C R E A T O R HAS CREATOR LIKES REPLY OF H A S C R E A T O R REPLY OF

m− R

ab

G+

n1

firstName: Bryn lastName: Davies

n2

imageFile: photo33711.jpg creationDate: 2010-10-16 browserUsed: Firefox

n3

firstName: Jose lastName: Alonso

n8

creationDate: 2010-10-30 browserUsed: {Firefox, Safari }

n5

firstName: Jane lastName: Murray

n6

creationDate: 2010-10-30 browserUsed: Safari LIKES K N O W S K N O W S LIKES HAS CREATOR H A S C R E A T O R HAS CREATOR L I K E S REPLY OF HAS CREATOR REPLY OF

m+

Person

firstName: STRING lastName: STRING gender: STRING birthday: DATE

... Post

imageFile: STRING? creationDate: STRING browserUsed: STRING

... Comment

creationDate: STRING browserUsed: STRING

...

KNOWS HAS CREATOR H A S C R E A T O R LIKES LIKES R E P L Y O F R E P L Y O F

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Descriptive updates: example

P

a b

G

n1

firstName: Bryn lastName: Davies

n2

imageFile: photo33711.jpg creationDate: 2010-10-16 browserUsed: Firefox

n3

firstName: Jose lastName: Alonso

n4

creationDate: 2010-10-30 browserUsed: Firefox

n5

firstName: Jane lastName: Murray

n6

creationDate: 2010-10-30 browserUsed: Safari

n7

creationDate: 2010-10-30 browserUsed: Safari LIKES K N O W S K N O W S LIKES HAS CREATOR H A S C R E A T O R HAS CREATOR LIKES REPLY OF H A S C R E A T O R REPLY OF

m− R

ab

G+

n1

firstName: Bryn lastName: Davies

n2

imageFile: photo33711.jpg creationDate: 2010-10-16 browserUsed: Firefox

n3

firstName: Jose lastName: Alonso

n8

creationDate: 2010-10-30 browserUsed: {Firefox, Safari }

n5

firstName: Jane lastName: Murray

n6

creationDate: 2010-10-30 browserUsed: Safari LIKES K N O W S K N O W S LIKES HAS CREATOR H A S C R E A T O R HAS CREATOR L I K E S REPLY OF HAS CREATOR REPLY OF

m+

Person

firstName: STRING lastName: STRING gender: STRING birthday: DATE

... Post

imageFile: STRING? creationDate: STRING browserUsed: STRING

... Comment

creationDate: STRING browserUsed: STRING

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KNOWS HAS CREATOR H A S C R E A T O R LIKES LIKES R E P L Y O F R E P L Y O F

Person

firstName: STRING lastName: STRING gender: STRING birthday: DATE

... Message

language: STRING? imageFile: STRING? creationDate: STRING lastName: TIMESTAMP browserUsed: STRING locationIP: DATE

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KNOWS HAS CREATOR LIKES REPLY OF

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Prototype

  • Prototype system implemented in the regraph Python library

(based on Neo4j PGs, see on GitHub https://github.com/Kappa-Dev/ReGraph)

  • We convert rules + matchings to openCypher queries
  • regraph generalizes schema/data relation to hierarchies of

graphs.

regraph

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Remarks

Couple of technical issues:

  • no native support for node cloning and node merge (we wrote

huge unreadable queries);

  • no way to set properties by dynamic keys (we use APOC).

Pre-print available: Angela Bonifati (UCBL1), Peter Furniss (Neo4j), Alastair Green (Neo4j), Russ Harmer (CNRS), Eugenia Oshurko (ENSL), Hannes Voigt (Neo4j), Schema Validation and Evolution for Graph Databases, https://arxiv.org/abs/1902.06427