HDBTracker
Weimo Liu, Saad Bin Suhaim, Saravanan Thirumuruganathan, Nan Zhang, Gautam Das, Ali Jaoua · Proceedings of the VLDB Endowment · 2014
Numerous web databases, e.g., amazon.com, eBay.com, are "hidden" behind (i.e., accessible only through) their restrictive search and browsing interfaces. This demonstration showcases HDBTracker, a web-based system that reveals and tracks (the changes of) user-specified aggregate queries over such hidden web databases, especially those that are frequently updated, by issuing a small number of search queries through the public web interfaces of these databases. The ability to track and monitor aggregates has applications over a wide variety of domains - e.g., government agencies can track COUNT of openings at online job hunting websites to understand key economic indicators, while businesses can track the AVG price of a product over a basket of e-commerce websites to understand the competitive landscape and/or material costs. A key technique used in HDBTracker is RS-ESTIMATOR, the first algorithm that can efficiently monitor changes to aggregate query answers over a hidden web database.