Abstract
This chapter presents a framework that makes it possible to introduce fuzzy preferences in queries over graph databases. It discusses implementation issues for the implementation of such a framework. The chapter introduces the notion of graph databases and preliminary notions concerning fuzzy set theory. It also presents the contributions of the scientific literature that allow for a flexible querying of crisp and fuzzy graph databases. These contributions choose the same approach which consists in extending a query language in order to introduce fuzzy preferences in graph pattern queries. Both these approaches consider the extension of the Cypher query language implemented in the Neo4j graph database management system. The chapter then presents a pioneer work that extends the Cypher language in order to express fuzzy preference queries over attributes, nodes and relationships in order to query a crisp graph database.