We survey foundational features underlying modern graph query languages. We first
discuss two popular graph data models: edge-labelled graphs, where nodes are connected …

As graph databases become widespread, the International Organization for Standardization
(ISO) and International Electrotechnical Commission (IEC) have approved a project to create …

RDF question/answering (Q/A) allows users to ask questions in natural languages over a
knowledge base represented by RDF. To answer a national language question, the existing …

This paper provides an in-depth and diversified analysis of the Wikidata query logs, recently
made publicly available. Although the usage of Wikidata queries has been the object of …

The original SPARQL proposal was often criticized for its inability to navigate through the
structure of RDF documents. For this reason property paths were introduced in SPARQL 1.1 …

Graph databases have received a lot of attention as they are particularly useful in many
applications such as social networks, life sciences and the semantic web. Various …

In this work, we study two simple yet general complexity classes, based on logspace Turing
machines, that provide a unifying framework for efficient query evaluation in areas such as …

The development of practical query languages for graph databases runs well ahead of the
underlying theory. The ISO committee in charge of database query languages is currently …

Regular path queries (RPQs) are a central component of graph databases. We investigate
decision-and enumeration problems concerning the evaluation of RPQs under several …

We investigate the problem of learning graph queries by exploiting user examples. The input
consists of a graph database in which the user has labeled a few nodes as positive or …