Deep web search: an overview and roadmap

We review the state-of-the-art in deep web search and propose a novel classification scheme to better compare deep web search systems. The current binary classification (surfacing versus virtual integration) hides a number of implicit decisions that must be made by a developer. We make these decisions explicit by distinguishing 7 system aspects that describe a system in terms of its functionality (what it can, and what it cannot do) and in terms of its solution to a specific problem. We then motivate the need for a search system which has a single-field free-text query interface that supports real-time structured search over multiple sources. To this end, we discuss two possible federated architectures and state the scientific challenges. Finally, we present the findings of our ongoing project and briefly outline related work to free-text interfaces over structured data.