中文摘要：

关系数据库模式和本体间映射是语义网研究中的一个重要问题．首先，给出关系数据库模式和本体间映射的形式化定义，并从建模思想和应用场景两个方面分析问题的难点．根据3个不同角度，即模型转换的途径、映射策略的适用范围以及映射结果的表达形式，调研当前存在的多种解决途径．在此基础上，进一步介绍并比较6个具有代表性的关系数据库模式和本体间映射的工具．最后，讨论存在的挑战，并指出未来可能的研究方向．

英文摘要：

Ontologies proliferate with the growth of the semantic Web. To date, however, most of the data on the Web are still stored in relational databases. Therefore, it is important to establish interoperability between relational databases and ontologies for creating a Web of data. An effective way to achieve such interoperability is to discover mappings between relational database schemas and ontologies. In this paper, some definitions in terms of mapping between a relational database schema and an ontology are firstly presented, and two major difficulties are analyzed from the standpoints of model construction and concrete application context. Then, a large number of popular existing solutions are surveyed according to three different facets, i.e., the approaches of model transformation （e. g. , transforming ontologies to relational database schemas, transforming relational database schemas to ontologies, or transforming both relational database schemas and ontologies to medium models）, the scopes of mapping strategies （e.g., automatization, and number of relational database schemas and ontologies）, and the expressions of mapping results （e.g., simple correspondences, or semantic mappings）. In addition, six representative mapping tools are introduced and compared with each other based on the three different facets mentioned above, and their unique features are highlighted in details. Finally, some remaining challenges are discussed, and some future research directions are also pointed out.