A Relational Calculus with Set Operators, Its Safety, and Equivalent Graphical Languages
IEEE Transactions on Software Engineering
Safety and translation of relational calculus
ACM Transactions on Database Systems (TODS)
A logical query language for hypertext systems
Hypertext: concepts, systems and applications
How to fit generalized quantifiers into terminological logics
ECAI '92 Proceedings of the 10th European conference on Artificial intelligence
Domain independence and the relational calculus
Acta Informatica
Foundations of Databases: The Logical Level
Foundations of Databases: The Logical Level
Improving SQL with Generalized Quantifiers
ICDE '95 Proceedings of the Eleventh International Conference on Data Engineering
Non-linear prefixes in query languages
Proceedings of the twenty-sixth ACM SIGMOD-SIGACT-SIGART symposium on Principles of database systems
Safety, domain independence and translation of complex value database queries
Information Sciences: an International Journal
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We define QLGQ, a query language with generalized quantifiers, which uses only conjuction to combine formulas, the rest of its expressive power coming from generalized quantification. However, the language is not safe. A safe (and domain independent) sublanguage (SQLGQ) is defined; the definition uses properties of geralized quantifiers as well as (minimal) syntax limitations on formulas, and is motivated on semantical grounds, unlike most past approaches which are purely syntactic. We prove that SQLGQ subsumes RC/S*, one of the largest classes of safe languages proposed in the literature. Given these results, we propose that the most useful type of quantification for query languages is relativized quantification, in which the scope of the quantifier is made explicit as part of the query, and give this idea a technical form using generalized quantifiers. Finally, we extend work by Hull and Su on alternative semantics for first-order logic (FOL) to this new framework and propose some open questions for further research. 2001 Elsevier science B.V. All rights reserv