Integrating data warehouses with web data : a survey

This paper surveys the most relevant research on combining Data Warehouse (DW) and Web data. It studies the XML technologies that are currently being used to integrate, store, query, and retrieve Web data and their application to DWs. The paper reviews different DW distributed architectures and the use of XML languages as an integration tool in these systems. It also introduces the problem of dealing with semistructured data in a DW. It studies Web data repositories, the design of multidimensional databases for XML data sources, and the XML extensions of OnLine Analytical Processing techniques. The paper addresses the application of information retrieval technology in a DW to exploit text-rich document collections. The authors hope that the paper will help to discover the main limitations and opportunities that offer the combination of the DW and the Web fields, as well as to identify open research line

Decision making on operational data: a remote approach to distributed data monitoring

Information gathering and assimilation is normally performed by data mining tools and Online analytic processing (OLAP) operating on historic data stored in a data warehouse. Data mining and OLAP queries are very complex, access a significant fraction of a database and require significant time and resources to be executed. Therefore, it has been impossible to draw the data analysis benefits in operational data environments. When it comes to analysis of operational (dynamic) data, running complex queries on frequently changing data is next to impossible. The complexity of active data integration increases dramatically in distributed applications which are very common in automated or e-commerce applications. We suggest a remote data analysis approach to find hidden patterns and relationships in distributed operational data, which does not adversely affect routine transaction processing. Distributed data integration on frequently updated data has been performed by analysing SQL commands coming to the distributed databases and aggregating data centrally to produce a real-time view of fast changing data. This approach has been successfully evaluated on data sources for over 30 data sources for hotel properties. This paper presents the performance results of the method, and its comparative study of the state-of-the art data integration techniques. The remote approach to data integration and analysis has been built into a scalable data monitoring system. It demonstrates the ease of application and performance results of operational data integration

SETL: A programmable semantic extract-transform-load framework for semantic data warehouses

In order to create better decisions for business analytics, organizations increasingly use external structured, semi-structured, and unstructured data in addition to the (mostly structured) internal data. Current Extract-Transform-Load (ETL) tools are not suitable for this “open world scenario” because they do not consider semantic issues in the integration processing. Current ETL tools neither support processing semantic data nor create a semantic Data Warehouse (DW), a repository of semantically integrated data. This paper describes our programmable Semantic ETL (SETL) framework. SETL builds on Semantic Web (SW) standards and tools and supports developers by offering a number of powerful modules, classes, and methods for (dimensional and semantic) DW constructs and tasks. Thus it supports semantic data sources in addition to traditional data sources, semantic integration, and creating or publishing a semantic (multidimensional) DW in terms of a knowledge base. A comprehensive experimental evaluation comparing SETL to a solution made with traditional tools (requiring much more hand-coding) on a concrete use case, shows that SETL provides better programmer productivity, knowledge base quality, and performance.Peer ReviewedPostprint (author's final draft