Mode of access: World Wide Web.

System requirements: Adobe Acrobat Reader.

Part of: Synthesis digital library of engineering and computer science.

Includes bibliographical references (pages 143-163).

1. Introduction --

2. Data models -- 2.1 Property graph model -- 2.2 Variations of the PGM -- 2.2.1 Specializations -- 2.2.2 Structural extensions -- 2.2.3 Data representation extensions -- 2.2.4 Summary -- 2.3 Bibliographic and historical notes --

3. Query languages -- 3.1 Basic functionality -- 3.1.1 Regular path queries -- 3.1.2 Conjunctive graph queries -- 3.1.3 Conjunctive regular path queries -- 3.1.4 Unions of conjunctive regular path queries -- 3.1.5 Relation algebra -- 3.2 Regular property graph queries -- 3.2.1 Regular property graph logic -- 3.2.2 Regular property graph algebra -- 3.2.3 Equivalence and complexity of RPGLog and RPGA -- 3.3 RPGQ in context -- 3.3.1 Important fragments of RPGQ -- 3.3.2 Extending RPGQ for composability -- 3.3.3 RPGQ and practical graph query languages -- 3.4 Bibliographic and historical notes --

4. Constraints -- 4.1 Preliminaries -- 4.2 Graph functional dependencies -- 4.2.1 Syntax -- 4.2.2 Semantics -- 4.2.3 Satisfiability -- 4.2.4 Implication -- 4.2.5 Validation -- 4.3 Graph entity dependencies -- 4.3.1 Definition and special cases -- 4.3.2 Preliminaries -- 4.3.3 Chasing graph entity dependencies -- 4.3.4 Satisfiability, implication, and validation -- 4.3.5 Extension to graph denial constraints -- 4.3.6 Applications and practical impact of graph dependencies -- 4.4 Other constraints for graph data management -- 4.4.1 Graph neighborhood constraints -- 4.4.2 Graph-to-graph constraints -- 4.5 Bibliographic and historical notes --

5. Query specification -- 5.1 Path query specification -- 5.1.1 The definability problem for graph queries -- 5.1.2 Complexity of definability for graph queries -- 5.1.3 From definability to learnability of graph queries -- 5.1.4 Interactive graph query specification -- 5.2 Graph searching for querying -- 5.3 Query-driven graph exploration -- 5.4 Bibliographic notes --

6. Data structures and indexes -- 6.1 Conceptual schemas of PGM representation -- 6.2 Direct representation of ternary relations -- 6.2.1 Value compression -- 6.2.2 Value indexing -- 6.3 Pivoted representation of ternary relations -- 6.4 Adjacency indexing -- 6.4.1 Uncompressed adjacency representation -- 6.4.2 Compressed adjacency representation -- 6.5 Reachability indexing -- 6.5.1 General considerations -- 6.5.2 Techniques -- 6.6 Structural indexing -- 6.7 Bibliographic and historical notes --

7. Query processing -- 7.1 Query pipeline -- 7.2 Subgraph matching queries -- 7.2.1 DFS-based algorithms -- 7.2.2 BFS-based algorithms -- 7.2.3 Discussion -- 7.3 Regular path queries -- 7.3.1 Relational algebra and datalog-based approaches -- 7.3.2 Finite automata-based approaches -- 7.4 Unions of conjunctive regular path queries -- 7.5 Bibliographic and historical notes --

8. Physical operators -- 8.1 Transitive closure -- 8.2 Multi-way joins -- 8.3 Cardinality estimation -- 8.3.1 Cardinality of paths -- 8.3.2 Cardinality of patterns -- 8.4 Further optimizations -- 8.5 Bibliographic and historical notes --

9. Research challenges -- Bibliography -- Authors' biographies.

Abstract freely available; full-text restricted to subscribers or individual document purchasers.

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Graph data modeling and querying arises in many practical application domains such as social and biological networks where the primary focus is on concepts and their relationships and the rich patterns in these complex webs of interconnectivity. In this book, we present a concise unified view on the basic challenges which arise over the complete life cycle of formulating and processing queries on graph databases. To that purpose, we present all major concepts relevant to this life cycle, formulated in terms of a common and unifying ground: the property graph data model--the pre-dominant data model adopted by modern graph database systems. We aim especially to give a coherent and in-depth perspective on current graph querying and an outlook for future developments. Our presentation is self-contained, covering the relevant topics from: graph data models, graph query languages and graph query specification, graph constraints, and graph query processing. We conclude by indicating major open research challenges towards the next generation of graph data management systems.

Also available in print.

Title from PDF title page (viewed on November 1, 2018).