Query Processing based on complex object types

In application areas where the data management system has to deal with a large number of complex data objects with a wide variety of types, the system must be able to process queries containing both conditions on the schema of the data objects and on the values of the data objects. In this paper we will focus on a particular phase in query processing on a data base of complex objects called Type-Level Query Processing. In this phase, the query is analyzed, completed, and transformed on the basis of the the defintions of the complex object types. We will present, in particular, the techniques used in the ESPRIT project MULTOS. In this project, a data server has been implemented in which data objects are constituted by multimedia documents with complex internal structures.