Query processing in the aqualogic data services platform

BEA recently introduced a new middleware product called the Aqua-Logic Data Services Platform (ALDSP). The purpose of ALDSP is to make it easy to design, develop, deploy, and maintain a data services layer in the world of service-oriented architecture (SOA). ALDSP provides a declarative foundation for building SOA applications and services that need to access and compose information from a range of enterprise data sources; this foundation is based on XML, XML Schema, and XQuery. This paper focuses on query processing in ALDSP, describing its overall query processing architecture, its query compiler and runtime system, its distributed query processing techniques, the translation of XQuery plan fragments into SQL when relational data sources are involved, and the production of lineage information to support updates. Several XQuery extensions that were added in support of requirements related to data services are also covered.