Summary
Complex logical query answering (CLQA) is a task of graph machine learning that involves multi-hop logical reasoning over massive graphs. In this paper, a survey of CLQA is provided with a focus on Neural Graph Databases (NGDBs) which enhance query answering in incomplete graphs. The paper introduces a framework for NGDBs including a Neural Graph Storage and a Neural Query Engine. The text discusses the challenges with traditional graph databases and the benefits of using NGDBs. Various aspects of graph databases, modeling, queries, datasets, and metrics are explored. The paper concludes with future research directions and applications of NGDBs.