Browsing Large Online Data Tables Using Generalized Query Previews (2001)

Companies, government agencies, and other organizations are making their data available to the world over the Internet. They often use large online relational tables for this purpose. Users query such tables with front-ends that typically use menus or form fillin interfaces, but these interfaces rarely give users information about the contents and distribution of the data. Such a situation leads users to waste time and network resources posing queries that have zero-hit or mega-hit results. Generalized query previews enable efficient browsing of large online databases by supplying data distribution information to the users. The data distribution information provides continuous feedback about the size of the result set as the query is being formed. Our paper presents a user interface architecture and discusses recent experimental findings. Our prototype system, ExpO, provides a flexible user interface for research and testing. The user study shows that for exploratory querying tasks, generalized query previews speed user performance and reduce network load.