Graph databases are now playing an important role because they allow us to overcome some limitations of relational databases. In particular, graph databases differ from relational databases in that the topology of data is as important as the data itself. Thus, typical graph database queries are navigational, asking whether some nodes are connected by paths satisfying some specific properties.
While relational databases were designed upon logical and algebraic foundations, the development of graph databases has been quite ad-hoc. In this sense, the aim of this paper is to provide them with some logical foundations. More precisely, in previous work we introduced a navigational logic, called GNL (Graph Navigational Logic) that allows us to describe graph navigational properties, and which is equipped with a deductive tableau method that we proved to be sound and complete.
In this presentation we will introduce a new formal model for property graphs. Then, we will show how graph queries à la Cypher can be expressed using a fragment of GNL, defining for them a logical and an operational semantics, based on the inference rules for GNL. Finally, we show that both semantics are equivalent.
Please note that the meeting will be recorded and live-streamed to YouTube: