The Rd-tree: an Index Structure for Sets

The implementation of complex types in Object-Relational database systems requires the development of efficient access methods. In this paper we describe the RD-Tree, an index structure for set-valued attributes. The RD-Tree is an adaptation of the R-Tree that exploits a natural analogy between spatial objects and sets. A particular engineering difficulty arises in representing the keys in an RD-Tree. We propose several different representations, and describe the tradeoffs of using each. An implementation and validation of this work is underway in the SHORE object repository.