  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.
