Skyline and ranking queries are two of the most used tools to manage large data sets. The former is based on non-dominance, while the latter on a scoring function. Despite their effectiveness, they have some drawbacks like the result size or the need for a utility function that must be taken into account. To do this, in the last years, new kinds of queries, called flexible skyline queries, have been developed. In the present article, a description of skyline and ranking queries, f-skyline queries and a comparison among them are provided to highlight the improvements achieved and how some limitations have been overcome.

翻译：暂无翻译