A screenshot of the DiscoverySpace query 'SM022 SAGE Tags .99'. The SAGE data housed by the Discovery database are represented with three classes of resource: SAGE Libraries, SAGE Tags and Tag Sequences. A library represents an experiment performed on a tissue sample; a library has properties such as a name and a protocol and is composed of many thousands of SAGE tags. Each SAGE tag represents a discrete, physical result from a SAGE experiment, and has a quality score, a read identifier, in addition to ditag and linker flags. Each tag also has a tag sequence that represents the sequence of the tag, such as TTCATACACCTATCCCC. In this figure, the user is requesting those tags from the library SM022 that have a quality score ≥0.99 and were not extracted from duplicate ditags.