Edge Labelled Graphs and Property Graphs; a comparison from the user perspective

TL;DR

This study compares user acceptance of property graphs and edge-labelled graphs, focusing on modeling preferences, query interpretation accuracy, and implications for future graph data modeling and querying techniques.

Contribution

It provides empirical insights into user preferences and interpretation accuracy for property graphs versus edge-labelled graphs, informing modeling and querying practices.

Findings

Participants preferred nodes for location data, especially in Cypher.

No significant difference in query interpretation accuracy overall.

Specific query syntax differences affected interpretation accuracy.

Abstract

This study compares participant acceptance of the property graph and edge-labelled graph paradigms, as represented by Cypher and the proposed extensions to the W3C standards, RDF* and SPARQL*. In general, modelling preferences are consistent across the two paradigms. When presented with location information, participants preferred to create nodes to represent cities, rather than use metadata; although the preference was less marked for Cypher. In Cypher, participants showed little difference in preference between representing dates or population size as nodes. In RDF*, this choice was not necessary since both could be represented as literals. However, there was a significant preference for using the date as metadata to describe a triple containing population size, rather than vice versa. There was no significant difference overall in accuracy of interpretation of queries in the two paradigms; although in one specific case, the use of a reverse arrow in Cypher was interpreted significantly more accurately than the ^ symbol in SPARQL. Based on our results and on the comments of participants, we make some recommendations for modellers. Techniques for reifing RDF have attracted a great deal of research. Recently, a hybrid approach, employing some of the features of property graphs, has claimed to offer an improved technique for RDF reification. Query-time reasoning is also a requirement which has prompted a number of proposed extensions to SPARQL and which is only possible to a limited extent in the property graph paradigm. Another recent development, the hypergraph paradigm enables more powerful query-time reasoning. There is a need for more research into the user acceptance of these various more powerful approaches to modelling and querying. Such research should take account of complex modelling situations.