QueryBuilder can be used on advanced search engine pages, administration backends, etc. to build complex queries or filters. It is highly customisable and can be used with many jQuery widgets like autocompleters and sliders.
It outputs a structured JSON of rules which can be easily parsed to create SQL/NoSQL/whatever queries.
B. Howe, G. Cole, N. Khoussainova, and L. Battle. Proceedings of the 2011 ACM SIGMOD International Conference on Management of data, page 1319--1322. New York, NY, USA, ACM, (2011)
D. Akehurst, and B. Bordbar. International Conference on the Unified Modeling Language (UML), 2185/2001, page 91-103. Toronto, (October 2001)Dated; refers to OCL 1. Most suggestions have been implemented in OCL 2..