IMPLEMENTATION OF ALGEBRA FOR QUERYING WEB DATA SOURCES
Iztok Savnik · 2008
The paper presents the implementation of query execution system Qios. It serves as a lightware system for the manipulation of XML data. Qios employs the relational technology for query processing. The main aim in the implementation is to provide a querying system that is easy to use and does not require any additional knowledge about the internal representation of data. The system provides robust and simple solutions for many design problems. We aimed to simplify the internal structures of query processors rooted in the design of relational and object-relational query processors. We propose efficient internal data structures for the representation of queries during all phases of query execution. The query optimization is based on dynamic programming and uses beam search to reduce the time complexity. The data structure for storing queries provides efficient representation of queries during the optimization process and the simple means to explore plan caching. Finally, main memory indices can be created on-the-fly to support the evaluation of queries.