APPLYING QUERY BY EXAMPLE IN OCL FOR PLATFORM-INDEPENDENT PROGRAMMING
Grzegorz Fałda, Wiktor Filipowicz, Piotr Habela, Krzysztof Stencel, Kazimierz Subieta, Krzysztof Kaczmarski · 2010
Precise modelling of behaviour is an area where programming meets modelling, and textual syntax competes with a visual one. By developing a UML based platform-independent framework, we aimed to find a visual syntax aid to make the language more approachable to stakeholders, while taking advantage of existing UML syntax intuitions and offering a truly higher level of abstraction. Our solution consists of seamlessly integrated UML Actions and the Object Constraint Language (OCL) as a database query language, featuring both a textual and a visual syntax. In this paper we describe a declarative, Query by Example (QBE)-based approach to visualizing OCL expressions over a UML object-oriented model instance, to be used inside of textual or visual imperative statements. Such visual OCL expressions can also be used as ad-hoc queries. The paper presents a choice of visual syntax and describes its underlying semantics.