6.5. Related work

As several models have been proposed to represent data having an implicit or explicit graph structure (see [ANG 08] for an overview of these models), the literature includes a variety of query languages for graphs. The authors of [ANG 08], [WOO 12] and [BAR 13] proposed complementary surveys of graph query languages defined in the past 25 years, including languages for querying graph-based object databases, semistructured data, social networks and Semantic Web data. The authors of [BAR 13] focused on theoretical query languages for graph databases and emphasized that graph database management systems still lack query languages with a clear syntax and semantics. This is the problem that we addressed here.

Functionalities that should be offered by a language for querying the topology of a crisp graph database are exhibited in [ANG 05, ANG 12, CIG 12, ANG 13, WOO 12]. We summarize these (non-exclusive) functionalities hereafter, focusing on selection statements of the DML...