1 QUERY LANGUAGES WITH GENERALIZED QUANTIFIERS

Various existing query languages allow queries with embedded sub-queries as well as sub-query comparison statements. It is often argued that these features enhance the declarativeness of the query language. We establish a link between between the phenomenon of sub-query syntax in query languages and the theory of generalized quantifiers as it was introduced by Barwise and Cooper in linguistics. Having es-tablished this link, we formulate and defend a thesis which states that most natural queries can be formulated as a conjunction of first-order predicate statements and set-predicate statements over sub-queries. We also introduce the language QLGQ which is designed in accordance with this thesis. We conclude by showing how various exist-ing query languages have implicitly adopted generalized quantifiers and discuss some related features of these languages.