SIGMOD Officers , Committees , and Awardees Chair Vice-Chair Secretary /

Skyline queries are a popular way to obtain preferred answers from the database by providing only the orderings of attribute values. The result of a skyline query consists of those input tuples for which there is no input tuple having better or equal values in all the attributes and a better value in at least one attribute. In this article, we summarize the basic notions and properties of skyline queries, and discuss their extensions and generalizations. In particular, we consider skyline algorithms and skyline cardinality issues.