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Publication and Maintenance of Relational Data in Enterprise Knowledge Graphs (Revised Version)

Vânia Maria Ponte Vidal, Valéria Magalhães Pequeno, Marco Antonio Casanova, Narciso Arruda, Carlos Brito

TL;DR

This article proposes a formal framework for constructing the materialized data graph for an RDB2RDF view and for incrementally maintaining the view's data graph.

Abstract

Enterprise knowledge graphs (EKGa) are a novel paradigm for consolidating and semantically integrating large numbers of heterogeneous data sources into a comprehensive dataspace. The main goal of an EKG is to provide a data layer that is semantically connected to enterprise data, so that applications can have integrated access to enterprise data sources through that semantic layer. To make legacy relational data sources accessible through the organization's knowledge graph, it is necessary to create an RDF view of the underlying relational data (RDB2RDF view). An RDB2RDF view can be materialized to improve query performance and data availability. However, a materialized RDB2RDF view must be continuously maintained to reflect updates over the relational database. This article proposes a formal framework for constructing the materialized data graph for an RDB2RDF view and for incrementally maintaining the view's data graph. The article also presents an architecture and algorithms for implementing the proposed framework.

Publication and Maintenance of Relational Data in Enterprise Knowledge Graphs (Revised Version)

TL;DR

This article proposes a formal framework for constructing the materialized data graph for an RDB2RDF view and for incrementally maintaining the view's data graph.

Abstract

Enterprise knowledge graphs (EKGa) are a novel paradigm for consolidating and semantically integrating large numbers of heterogeneous data sources into a comprehensive dataspace. The main goal of an EKG is to provide a data layer that is semantically connected to enterprise data, so that applications can have integrated access to enterprise data sources through that semantic layer. To make legacy relational data sources accessible through the organization's knowledge graph, it is necessary to create an RDF view of the underlying relational data (RDB2RDF view). An RDB2RDF view can be materialized to improve query performance and data availability. However, a materialized RDB2RDF view must be continuously maintained to reflect updates over the relational database. This article proposes a formal framework for constructing the materialized data graph for an RDB2RDF view and for incrementally maintaining the view's data graph. The article also presents an architecture and algorithms for implementing the proposed framework.
Paper Structure (19 sections, 15 equations, 7 figures, 4 tables, 1 algorithm)

This paper contains 19 sections, 15 equations, 7 figures, 4 tables, 1 algorithm.

Table of Contents

  1. Introduction
  2. Related Work
  3. Object Preserving RDB2RDF Views
  4. Basic Concepts and Notation
  5. Specification of Object Preserving RDB2RDF View
  6. Case Study: MusicBrainz_RDF
  7. Materialization of an RDB2RDF view
  8. Formal Framework for Computing Correct Changesets for RDB2RDF Views
  9. Overview
  10. Formal Definitions for Computing Changesets
  11. Computation of the Changeset $\langle \Delta^{-}(u), \Delta^{+}(u) \rangle$
  12. Computation of $\Delta^{-}(u)$
  13. Computation of $\Delta^{+}(u)$
  14. Case Study: Computing Changeset for MusicBrainz_RDF view
  15. Identifying Relevant Transformation Rules
  16. ...and 4 more sections

Figures (7)

  • Figure 1: The problem of computing the correct changeset for RDB2RDF View.
  • Figure 2: (a) Fragment of MusicBrainz Schema and (b) Fragment of MusicBrainz_RDF View Ontology.
  • Figure 3: State Example for Relations in Figure \ref{['f-rdb']}(a).
  • Figure 4: Database State after the update $\textit{u}$.
  • Figure 5: Generic AFTER statement-level trigger to compute the changeset $\langle \Delta^{-}(u), \Delta^{+}(u) \rangle$ for an update $u = (D, I)$ on relation $R$.
  • ...and 2 more figures

Theorems & Definitions (17)

  • definition 1: Foreign Key
  • definition 2: Relational Path
  • definition 3: Relations of a Relational Path
  • definition 4: Connected to
  • definition 5: Related Tuples w.r.t. a Path
  • definition 6
  • definition 7: RDF State of a Pivot Tuple under a Rule
  • definition 8: RDF State of a Pivot Tuple
  • definition 9: RDF State of an RDB2RDF View
  • definition 10: updates, insertions and deletions
  • ...and 7 more