Federated database systems for managing distributed, heterogeneous, and autonomous databases
ACM Computing Surveys (CSUR) - Special issue on heterogeneous databases
Query caching and optimization in distributed mediator systems
SIGMOD '96 Proceedings of the 1996 ACM SIGMOD international conference on Management of data
OLAP solutions: building multidimensional information systems
OLAP solutions: building multidimensional information systems
SIGMOD '96 Proceedings of the 1996 ACM SIGMOD international conference on Management of data
Query optimization in the presence of limited access patterns
SIGMOD '99 Proceedings of the 1999 ACM SIGMOD international conference on Management of data
Extending OLAP querying to external object databases
Proceedings of the ninth international conference on Information and knowledge management
A powerful and SQL-compatible data model and query language for OLAP
ADC '02 Proceedings of the 13th Australasian database conference - Volume 5
Optimizing Queries Across Diverse Data Sources
VLDB '97 Proceedings of the 23rd International Conference on Very Large Data Bases
VLDB '99 Proceedings of the 25th International Conference on Very Large Data Bases
Cost Modeling and Estimation for OLAP-XML Federations
DaWaK 2000 Proceedings of the 4th International Conference on Data Warehousing and Knowledge Discovery
SSDBM '02 Proceedings of the 14th International Conference on Scientific and Statistical Database Management
Cost Modeling and Estimation for OLAP-XML Federations
DaWaK 2000 Proceedings of the 4th International Conference on Data Warehousing and Knowledge Discovery
Colorful XML: one hierarchy isn't enough
SIGMOD '04 Proceedings of the 2004 ACM SIGMOD international conference on Management of data
Analytical processing of XML documents: opportunities and challenges
ACM SIGMOD Record
Ix-cubes: iceberg cubes for data warehousing and olap on xml data
Proceedings of the sixteenth ACM conference on Conference on information and knowledge management
Managing quality properties in a ROLAP environment
CAiSE'06 Proceedings of the 18th international conference on Advanced Information Systems Engineering
Affordable web-based spatio-temporal applications for ad-hoc decisions
OTM'06 Proceedings of the 2006 international conference on On the Move to Meaningful Internet Systems: AWeSOMe, CAMS, COMINF, IS, KSinBIT, MIOS-CIAO, MONET - Volume Part II
On-demand multidimensional data integration: toward a semantic foundation for cloud intelligence
The Journal of Supercomputing
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The changing data requirements of today's dynamic business environments are not handled well by current OLAP systems. Physically integrating unexpected data into such systems is a long and time-consuming process making logical integration, i.e., federation, the better choice in many situations. The increasing use of Extended Markup Language (XML), e.g. in business-to-business (B2B) applications, suggests that the required data will often be available as XML data. This means that logical federations of OLAP and XML databases will be very attractive in many cases. However, for such OLAP-XML federations to be useful, effective optimization techniques for such systems are needed.In this paper we present novel techniques for query optimization in federations of OLAP and XML databases. The techniques include so-called inlining of XML data in OLAP predicates, caching, and pre-fetching. Experiments show that the proposed optimization techniques improve query execution times significantly. Furthermore, the performance of the optimized federation queries is comparable to the performance achieved with physical integration of the data, showing that our federated OLAP approach is indeed a feasible alternative to physical integration.