Qios - query service for processing Internet data

Query service for processing Internet data

QIOS - a system for quering and integration of Internet data

AUTHORS

Iztok SAVNIK, iztok.savnik@siol.net
Zahir TARI, RMIT, zahirt@cs.rmit.edu.au

SUMMARY

qios (v0.9) is a system for the manipulation of data from internet data sources. The system is intended to serve as the lightware kernel of a data manipulation server.

The main aims in the design of qios are to provide: the system for the manipulation of larger collections of data in a fast manner, various data manipulation functions from classical querying to data restructuring, and, the capabilities to organize, store and browse the data collections obtained from the Internet data sources on the local host. The system currently provides the interface for XML.

IMPLEMETATION

qios is implemented in Perl v5.6.0 which is one of the most widely used Web programming languages. Perl programming environment offers a rich and well-organized collection of Perl modules (CPAN) covering most of modern data formats as well as database interfaces.

qios v0.9 (alpha) is available as compressed tar file qios-0.9.alpha.tar.gz. Short instructions for the installation are presented in README.

QUERY EXECUTION

The query execution engine is rooted in the relational techniques for the query optimization and evaluation. The architecture of the query engine is developed on top of the object-relational data model using structural part of F-Logic as the formal basis.

To allow robust and flexible implementation of query engine the architecture uses a single form of query representation for all phases of query execution. Furthermore, the rule representation and processing is based on the query tree representation of query optimization rules and the use of graph (tree) matching algorithm for rule matching. More detailed presentation of qios query engine is given in man pages.

The query execution on the distributed data sources provides the opportunity to split the execution of a query so that the parts of queries that address solely collections from a single data source can be processed locally. The query optimization module and the cost functions of qios are implemented to process distributed queries. The query model can be viewed as the abstract data flow graph. The query evaluation engine for distributed execution of queries is to be completed.

MAN PAGES

The presentation of the qios query language, database environment, and basic system operations is given in the man pages of qios system. Man pages are used also for the documentation of the qios modules. The text versions of the man pages are:

qios -- main program
Glb -- global data structures
Parse -- query parsing
Que -- query manipulation
Optor -- query optimization
Cost -- cost function
Osm -- object storage manager
Rsm -- record storage manager
Rule -- rule processing
Eval -- query execution
Load -- data/xml loader

DOCUMENTS

I.Savnik, Z.Tari: Query Processing System for Web Data Sources. Working Notes, Apr 2001.
[postscript]
I.Savnik: Algebra for distributed data sources. Dagstuhl Seminar No. 99351 "Multimedia Database Support for Digital Libraries", Schloss Dagstuhl, Germany, Aug 1999.
[abstract]
I.Savnik, Z.Tari and T.Mohoric: QAL: A Query Algebra for Complex Objects. Int. Jnl on Data and Knowledge Engineering, 30(1), May 1999, pp. 57-94.
[postscript]
I.Savnik and Z.Tari: Querying Conceptual Schemata of Object-Oriented Databases. Proc. of the DEXA conference, Zurich, 1996.
[postscript]
I.Savnik, Z.Tari: Unifying Schema and Instance Levels of Object-Oriented Databases. Technical Report, Faculty of Computer Science, University of Ljubljana, Apr 1997.
[postscript]
I.Savnik, Z.Tari and T.Mohoric: Using Schema Information for Querying Databases. Proc. of the Int. Workshop on Reasoning about Structured Objects: Knowledge Representation Meets Databases, Bielefeld, Germany, 1995.
[postscript]