UML is the de-facto standard language for Object-Oriented analysis and design of information systems. Persistent storage and extraction of data in such systems is supported by databases and query languages. UML sustains many aspects of software engineering; however, it does not provide explicit facility for writing queries. It is crucial for any such query language to have, at least, the expressive power of Relational Algebra, which serves as a benchmark for evaluating its expressiveness. The combination of UML and OCL can form queries with the required expressive power. However, certain extensions to OCL are essential if it is to be used effectively as a Query Language. The adoption of the ideas presented in this paper will enable query expressions to be written using OCL, that are elegant and ideally suited for use in conjunction with UML data models. This technique is illustrated by expressing the UML equivalent of an example Relational data model and associated query expressions.
REF proves that the UML has the expressive power of the relational algebra and it is possible to use OCL as a query language.
On Querying UML Data Models with OCL
UML 2001 - The Unified Modeling Language. Modeling Languages, Concepts, and Tools. 4th International Conference
Computer Science