In recent years, NoSQL graph databases have received an increased interest in the research community. Various query languages have been developed to enable users to interact with a graph database (e.g. Neo4j), such as Cypher or Gremlin. Although the syntax of graph query languages can be learned, inexperienced users may encounter learning difficulties regardless of their domain knowledge or level of expertise. For this reason, the Query-By-Example approach has been used in relational databases over the years. In this paper, we demonstrate how a variation of this approach, the Trigger-By-Example approach, can be used to define triggers in graph databases, specifically Neo4j, as database mechanisms activated upon a given event. The proposed approach follows the Event-Condition-Action model of active databases, which represents the basis of a trigger. To demonstrate the proposed approach, a special graphical interface has been developed, which enables users to create triggers in a short series of steps. The proposed approach is tested on several sample scenarios.
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