openCypher

References

The evolution of the Cypher® language is driven by the openCypher Implementers Group via language proposals and requests. As an outcome, the openCypher community provides a number of artifacts.

However, many of these ideas are predated by academic work, and we provide here a list of publications, grouped by topic and ordered by date (earliest first). We additionally list documents, talks and slides pertaining to these topics.

Please note that this list is not exhaustive.

Index to sections

• Property graph data model and extensions
• GQL
• INCITS DM32 Ad Hoc on Property Graph Extensions to SQL
• Graph querying: regular path queries and graph pattern matching
• Cypher
• Cypher and SQL
• Multiple graphs, graph composition and operations
• Position papers and surveys
• General talks

Property graph data model and extensions

Publications

1. Martínez-Bazan, N., Muntés-Mulero, V., Gómez-Villamor, S., Nin, J., Sánchez-Martínez, M-A., and Larriba-Pey, J-L. DEX: High-performance Exploration on Large Graphs for Information Retrieval. In Proc. 16th ACM Conference on Information and Knowledge Management (CIKM), pages 573–582, 2007.
2. Rodriguez, M. A., and Neubauer, P. Constructions from Dots and Lines. Bulletin of the Association for Information Science and Technology, August 2010.
3. Hartig, O. Reconciliation of RDF* and Property Graphs. CoRR, abs/1409.3288, 2014.
4. Junghanns, M., Petermann, A., Gómez, K., and Rahm, E. GRADOOP: Scalable Graph Data Management and Analytics with Hadoop. CoRR abs/1506.00548, 2015.
5. Angles, R., Arenas, M., Barceló, P., Hogan, A., Reutter, J., and Vrgoč, D. Foundations of Modern Query Languages for Graph Databases. ACM Computing Surveys, Volume 50 Issue 5, November 2017.
6. Marton, J., Szárnyas, G. and Varró, D. Formalising openCypher Graph Queries in Relational Algebra. In Proc. 21st European Conference on Advances in Databases and Information Systems (ADBIS), 2017.
7. Moffitt, V. Z., and Stoyanovich, J. Temporal Graph Algebra. In Proc. 16th International Symposium on Database Programming Languages (DBPL), 2017.

Links

1. Textual description of the Property Graph Model: [link]
2. Defining a Property Graph: [link]

GQL

• GQL Project Proposal
• The GQL Manifesto
• A proposal to the database industry: Not three but one: GQL
• Working towards a New Work Item for GQL, to complement SQL PGQ
• GQL Scope and Features [Full paper|Digest presentation at WG3 meeting in Brisbane, 2019|Overview]
• Comparative analysis of existing graph query languages: Phase 1

INCITS DM32 Ad Hoc on Property Graph Extensions to SQL

2018 and 2019 Contributions from Neo4 SQL working group

• Property Graph Data Model for SQL
• Aligning Cypher and SQL Graph Pattern Syntax
• Property Graph Querying roadmap and initial scope
• An overview of the recent history of Graph Query Languages
• Summary Chart of Cypher, PGQL, and G-Core
• Creating an Open Industry Standard for a Declarative Property Graph Query Language
• The Cypher Language 2017: Presentation to the LDBC Query Language Task Force
• Property Graph Schema
• Path Pattern Union [Full paper|Digest presentation at WG3 meeting in Arusha, Tanzania, 2019]

Graph querying: regular path queries and graph pattern matching

Publications

1. Cruz, I. F., Mendelzon A. O., and Wood, P. T. A graphical query language supporting recursion. In Proc. ACM SIGMOD, pages 323–330, 1987.
2. Wood, P. T. Query Languages for Graph Databases. SIGMOD Record, pages 50-60, 2012.
3. Barceló, P., Libkin, L., Lin, A. W., and Wood, P. T. Expressive Languages for Path Queries over Graph-Structured Data. ACM Transactions on Database Systems (TODS), pages 1-46, 2012.
4. Barceló, P., Libkin, L., and Reutter, J. L. Querying Regular Graph Patterns. ACM Journal, pages 1-54, 2014.
5. Angles, R., Arenas, M., Barceló, P., Hogan, A., Reutter, J., and Vrgoč, D. Foundations of Modern Query Languages for Graph Databases. ACM Computing Surveys, Volume 50 Issue 5, November 2017.
6. Libkin, L., Martens, W., and Vrgoč, D. Querying Graphs with Data. ACM Journal, pages 1-53, 2016.
7. van Rest, O., Hong, S., Kim, J., Meng, X., and Chafi, H. PGQL: A Property Graph Query Language. In Proc. 4th International Workshop on Graph Data-management Experiences & Systems (GRADES), 2016.

Cypher Improvement Proposals

1. CIP2017-02-06 Path Patterns
2. CIP2017-01-18 Configurable Pattern Matching Semantics

Talks

1. Conjunctive regular path queries: [slides]
   First openCypher Implementers Meeting, 8 February 2017 (Tobias Lindaaker, Neo4j)
2. Graph pattern matching semantics: [slides]
   First openCypher Implementers Meeting, 8 February 2017 (Oskar van Rest, Oracle)
3. Expressivity of regular path pattern queries: [slides]
   March 2017 (Tobias Lindaaker, Neo4j)
4. Path query patterns in Cypher (regular path queries): [slides]
   Second openCypher Implementers Meeting, 10 May 2017 (Tobias Lindaaker, Neo4j)
5. Path pattern queries - regular path queries - in Cypher: [slides] [recording]
   Second openCypher Implementers Group Meeting, 6 July 2017 (Tobias Lindaaker, Neo4j)
6. Configurable pattern matching semantics in Cypher: [slides] [recording]
   Third openCypher Implementers Group Meeting, 27 July 2017 (Stefan Plantikow, Neo4j)
7. Path Query Patterns in Cypher: [slides]
   Ad Hoc on SQL Extensions Property Graphs, 10 October 2017 (Tobias Lindaaker, Neo4j)

Cypher

Publications

1. Hölsch, J., and Grossniklaus, M. An Algebra and Equivalences to Transform Graph Patterns in Neo4j. In Proc. of the Workshops of the EDBT/ICDT Joint Conference, 2016.
2. Yang, M. A Study of Execution Strategies for openCypher on Apache Flink. Master's thesis, Eindhoven University of Technology., 2016.
3. Angles, R., Arenas, M., Barceló, P., Hogan, A., Reutter, J., and Vrgoč, D. Foundations of Modern Query Languages for Graph Databases. ACM Computing Surveys, Volume 50 Issue 5, November 2017.
4. Marton, J., Szárnyas, G. and Varró, D. Formalising openCypher Graph Queries in Relational Algebra. In Proc. 21st European Conference on Advances in Databases and Information Systems (ADBIS), 2017.
5. Junghanns, M., Kiessling, M., Averbuch, A., Petermann, A. and Rahm, E. Cypher-based Graph Pattern Matching in Gradoop. In Proc. 5th International Workshop on Graph Data-management Experiences & Systems (GRADES), 2017.
6. Steer, B.A., Alnaimi, A., Lotz, M.A.B.F.G., Cuadrado, F., Vaquero, L.M., and Varvenne, J. Cytosm: Declarative Property Graph Queries Without Data Migration. In Proc. 5th International Workshop on Graph Data-management Experiences & Systems (GRADES), 2017.
7. Kankanamge, C., Sahu, S., Mhedbhi, A., Chen, J., and Salihoglu, S. Graphflow: An Active Graph Database. In Proc. 2017 ACM SIGMOD International Conference on Management of Data, 2017.
8. Weber, J. H. GRAPE – A Graph Rewriting and Persistence Engine. In Proc. 10th International Conference on Graph Transformation (ICGT), 2017.

Talks

1. Formal semantics of SQL (and Cypher): [slides]
   First openCypher Implementers Meeting, 8 February 2017 (Paolo Guagliardo, University of Edinburgh)
2. Incremental graph queries for Cypher: [slides]
   First openCypher Implementers Meeting, 8 February 2017 (Gábor Szárnyas, József Marton, Budapest University of Technology and Economics)
3. Extended Property Graphs and Cypher on Gradoop: [slides]
   First openCypher Implementers Meeting, 8 February 2017 (Martin Junghanns, University of Leipzig)
4. Formal specification of Cypher: [slides]
   Second openCypher Implementers Meeting, 10 May 2017 (Nadime Francis, University of Edinburgh)
5. The ingraph project and incremental evaluation of Cypher queries: [slides]
   Second openCypher Implementers Meeting, 10 May 2017 (Gábor Szárnyas, József Marton, Budapest University of Technology and Economics)

Cypher and SQL

Talks and slides

1. ISO/INCITS initiatives on property graph querying in SQL: [slides] [recording]
   Third openCypher Implementers Group Meeting, 27 July 2017 (Jan Michels, Oracle, Group Chair: Ad Hoc on SQL Extensions Property Graphs)
2. SQL and Cypher (and PGQL): [slides] [recording]
   Third openCypher Implementers Group Meeting, 27 July 2017 (Alastair Green, Neo4j)
3. An overview of a proposal for SQL/Graph Query Procedures: [slides] [recording]
   Fourth openCypher Implementers Group Meeting, 17 August 2017 (Peter Furniss, Neo4j)
4. SQL Standards 2017: [slides]
   20 October 2017 (Keith W. Hare, SC32 WG3 Convenor, JCC Consulting, Inc.)

Multiple graphs, graph composition and operations

Publications

1. He, H., and Singh, A. K. Graphs-at-a-time: Query Language and Access Methods for Graph Databases. In Proc. 2008 ACM SIGMOD International Conference on Management of Data, 2008.
2. He, H., and Singh, A. K. Query Language and Access Methods for Graph Databases. Managing and Mining Graph Data, pages 125-160. Springer Publishing, 2010.
3. Junghanns, M., Petermann, A., Gómez, K., and Rahm, E. GRADOOP: Scalable Graph Data Management and Analytics with Hadoop. CoRR abs/1506.00548, 2015.
4. Junghanns, M., Petermann, A., Teichmann, N., Gómez, K., and Rahm, E. Analyzing extended property graphs with Apache Flink. In Proc. 1st ACM SIGMOD Workshop on Network Data Analytics (NDA), 2016.

Cypher Improvement Proposals

1. CIP2016-06-22 Nested Subqueries
2. CIP2017-03-29 Scalar Subqueries and List Subqueries
3. CIP2017-04-20 Query Combinators
4. CIP2017-06-18 Multiple Graphs

Talks

1. The case for multiple graph querying: [slides]
   First openCypher Implementers Meeting, 8 February 2017 (Alastair Green, Neo4j)
2. Virtual graphs and graph views in Cypher: [slides]
   First openCypher Implementers Meeting, 8 February 2017 (Hannes Voigt, Sascha Peukert, Technical University of Dresden; Michael Hunger, Neo4j)
3. Evolving Cypher for processing multiple graphs: slides
   First openCypher Implementers Meeting, 8 February 2017 (Stefan Plantikow, Neo4j)
4. Nested subqueries: [slides]
   Second openCypher Implementers Meeting, 10 May 2017 (Petra Selmer, Neo4j)
5. Query combinators: [slides]
   Second openCypher Implementers Meeting, 10 May 2017 (Stefan Plantikow, Neo4j)
6. Multiple graph processing: naming and addressing: [slides]
   Second openCypher Implementers Meeting, 10 May 2017 (Alastair Green, Neo4j)
7. Syntax and semantics of Cypher for multiple graphs: [slides]
   Second openCypher Implementers Meeting, 10 May 2017 (Stefan Plantikow, Neo4j)
8. Draft graph URI scheme: [document] [slides] [recording]
   Third openCypher Implementers Group Meeting, 27 July 2017 (Peter Furniss, Neo4j)
9. Multiple graphs in depth: [slides] [recording]
   Fourth openCypher Implementers Group Meeting, 17 August 2017 (Stefan Plantikow, Neo4j)
10. Nested, updating, and chained subqueries: [slides] [recording]
    Sixth openCypher Implementers Group Meeting, 19 October 2017 (Stefan Plantikow, Petra Selmer, Neo4j)
11. Scalar subqueries and list subqueries: [slides] [recording]
    Sixth openCypher Implementers Group Meeting, 19 October 2017 (Tobias Lindaaker, Neo4j)

Position papers and surveys

Publications

1. Angles, R., and Gutierrez C. Survey of graph database models. ACM Computing Survey, 40(1):1:1–1:39, 2008.
2. Sahu, S., Mhedhbi, A., Salihoglu, S., Lin J., and Özsu, M. T. The Ubiquity of Large Graphs and Surprising Challenges of Graph Processing. In Proceedings of the VLDB Endowment, Vol. 11, No. 4, 2017.

General talks

1. Introduction to Graph Data Management EDBT Summer School 2017, Genoa, Italy (Tobias Lindaaker, Neo4j)
2. Compiling openCypher graph queries with Spark Catalyst Montréal Spark meetup, December 2017, Canada (Gábor Szárnyas, Budapest University of Technology and Economics)
3. Cypher: an evolving query language for property graphs FOSDEM, February 2018, Brussels, Belgium (Stefan Plantikow, Neo4j)
4. Cypher for Apache Spark FOSDEM, February 2018, Brussels, Belgium (Martin Junghanns, Max Kiessling, Neo4j)
5. Graph-based analysis of JavaScript source code repositories FOSDEM, February 2018, Brussels, Belgium (Gábor Szárnyas, Budapest University of Technology and Economics)
6. openCypher: New Directions in Property Graph Querying EDBT/ICDT 2018 Joint Conference, March 2018, Vienna, Austria (Petra Selmer & Martin Junghanns, Neo4j)
7. Writing a Cypher Engine in Clojure Third Budapest Clojure Meetup, March 2018, Budapest, Hungary (Dávid Szakállas & Gábor Szárnyas, Budapest University of Technology and Economics)
8. GQL Scope & Features Graph Day, Austin, Texas, USA(Petra Selmer, Neo4j)