Abstract. We study, in the context of object/relational mapping tools, the problem of describing mappings between inheritance hierarchies and relational schemas. To this end, we introduce a novel mapping model, called M 2 ORM 2 +HIE , and investigate its mapping capabilities. We first show that M 2 ORM 2 +HIE subsumes three well-know basic representation strategies for mapping a hierarchy to relations. We then show that M 2 ORM 2 +HIE also allows expressing further mappings, e.g., where the three basic strategies are applied independently to different parts of a multi-level hierarchy. We describe the semantics of M 2 ORM 2 +HIE in term of how CRUD (i.e., Create, Read, Update, and Delete) operations on objects (in a hierarchy) can be translated into operations over a corresponding relational database. We also investigate correctness conditions.
Our technique is inspired in part by the work of Cabibbo and Carosi REF , discussed more complex mapping strategies for inheritance hierarchies, in which various strategies can be applied independently to parts of a multi-level hierarchy.
Managing inheritance hierarchies in object/relational mapping tools
CAiSE
Computer Science