Over the past 40 years, database management systems (DBMSs) have evolved to
provide a sophisticated variety of data management capabilities. At the same
time, tools for managing queries over the data have remained relatively
primitive. One reason for this is that queries are typically issued through
applications. They are thus debugged once and re-used repeatedly. This mode of
interaction, however, is changing. As scientists (and others) store and share
increasingly large volumes of data in data centers, they need the ability to
analyze the data by issuing exploratory queries.