Data stream query processing

Stream data are also generated naturally by (message-based) Web services, in which loosely coupled systems interact by exchanging high volumes of business data (e.g., purchase orders, retail transactions) tagged in XML (the lingua franca of Web services), forming continuous XML data streams. A central aspect of Web services is the ability to efficiently operate on these XML data streams executing queries (expressed in some XML query language) to continuously match, extract and transform parts of the XML data stream to drive legacy back-end business applications. The objective of this tutorial is to provide a comprehensive and cohesive overview of the key research results in the area of data stream query processing, both for SQL-like and XML query languages.