MOCQL: A Declarative Language for Ad-Hoc Model Querying

This paper starts from the observation that existing model query facilities are not easy to use, and are thus not suitable for users without substantial IT/Computer Science background. In an attempt to highlight this issue and explore alternatives, we have created the Model Constraint and Query Language (MOCQL), an experimental declarative textual language to express queries (and constraints) on models.

We introduce MOCQL by examples and its grammar, evaluate its usability by means of controlled experiments, and find that modelers perform better and experience less cognitive load when working with MOCQL than when working with OCL. While MOCQL is currently only implemented and validated for the different notations defined by UML, its concepts should be universally applicable.