Model-Driven Design of Graph Databases

Roberto De Virgilio, Antonio Maccioni and Riccardo Torlone

33rd edition of the International Conference on Conceptual Modeling (ER2014) – Atlanta, GA (U.S.A.)

Context (Theory)

ER 2014 Model-Driven Design of Graph Databases Atlanta, USA, 28th Oct 2014

Logics

ER

ModelsConcepts

Meta- Models

NoDB

NoSQL

NoSPARQL

AgileDevelopment

Schema-free

Semantics

Context (Practice)

ER 2014 Model-Driven Design of Graph Databases Atlanta, USA, 28th Oct 2014

Software engineers still reason at different abstraction levels

Data engineers still model their databases

We cannot give up modeling with all NoSQLs

Graph Databases

ER 2014 Model-Driven Design of Graph Databases Atlanta, USA, 28th Oct 2014

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Property Graph Model

ER 2014 Model-Driven Design of Graph Databases Atlanta, USA, 28th Oct 2014

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Graph DB Modeling: How?

Compact: Sparse: Dense: Reduces the number of data accesses

Can violate property graph constraints

Accesses and updates can be inefficient

Reduces number of joins

Needs human intervention for a semantic enrichment

ER 2014 Model-Driven Design of Graph Databases Atlanta, USA, 28th Oct 2014

Our 3-steps Approach

ER 2014 Model-Driven Design of Graph Databases Atlanta, USA, 28th Oct 2014

1) Generation of an oriented ER diagram

2) Partitioning of the elements (entities and relationships) of the obtained diagram

3) Definition of a template over the resulting partition.

Use case: ER

ER 2014 Model-Driven Design of Graph Databases Atlanta, USA, 28th Oct 2014

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Orienting the ER

ER 2014 Model-Driven Design of Graph Databases Atlanta, USA, 28th Oct 2014

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Use case: O-ER

ER 2014 Model-Driven Design of Graph Databases Atlanta, USA, 28th Oct 2014

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Partitioning the O-ER

ER 2014 Model-Driven Design of Graph Databases Atlanta, USA, 28th Oct 2014

Rule 1: if a node n is disconnected then it forms a group by itself.

Rule 2: if a node n has w−(n)>1 and w+(n)>0 then n forms a group by itself.

Rule 3: if a node n has w−(n)<2 and w+(n)<2 then n is added to the group of a node m such that there exists the edge (m, n) in the O-ER diagram.

Use case: partitioned O-ER

ER 2014 Model-Driven Design of Graph Databases Atlanta, USA, 28th Oct 2014

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Template of the Graph Database

ER 2014 Model-Driven Design of Graph Databases Atlanta, USA, 28th Oct 2014

A template describes homogeneous nodes occurring in a graph database and the ways they are connected.

A template is similar to a logical schema, but it is not a schema!

A template is derived by grouping together attributes of nodes in the partitioning.

Use case: the Template

ER 2014 Model-Driven Design of Graph Databases Atlanta, USA, 28th Oct 2014

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Use case: an instance

ER 2014 Model-Driven Design of Graph Databases Atlanta, USA, 28th Oct 2014

ER 2014 Model-Driven Design of Graph Databases Atlanta, USA, 28th Oct 2014

Empirical Results

sparse native strategy

our approach

ER 2014 Model-Driven Design of Graph Databases Atlanta, USA, 28th Oct 2014

Conclusion and Future WorkConceptual modeling of graph databases is useful and possible

Our methodology is systemindependent and aim at minimizing data accesses

We want to involve more aspects in the design process and verify the approach with other NoSQL

We are developing a tool that allows the developer to customize the modeling of this methodology by tuning on the parameters

Thanks for the Attention