Assessing the Support of ER and UML Class Diagrams during Maintenance Activities on Data Models

Abstract

We present the results of two controlled experiments carried out to compare the support given by the ER and UML class diagrams during the maintenance of data models. The experiments involved Master and Bachelor students performing maintenance tasks on data models represented by ER and UML class diagrams. The results reveal that the two notations give in general the same support. In particular, the correctness level achieved by a subject performing the task on data model represented by an ER diagram are comparable with the correctness level achieved by the same subject performing the task on a different data model represented by an UML class diagram. Moreover, by discriminating the levels of ability (high vs. low) and experience (graduate vs. undergraduate) of subjects we also provide some consideration about the influence of such factors on the correctness level achieved by subjects. In particular, we observe that UML class diagrams better support subjects with high ability than ER diagrams, while no difference can be observed considering subjects with low ability. Regarding the experience factor the results reveal no difference in the correctness level achieved by graduate and undergraduate students.

An experimental comparison of ER and UML class diagrams for data modelling

“…Recently, we compared ER and UML class diagrams from a maintainer perspective (De Lucia et al 2008b, c). In particular, in De Lucia et al (2008c) we reported the results of a controlled experiment and a replication aimed at analysing whether UML class diagrams are more comprehensible than ER diagrams.…”

“…Indeed, nowadays ER remains the most used notation to model databases and in some cases it complements UML in the design of software systems. In a recent small industrial survey carried out with our industrial we found that 4 of 13 contacted software companies usually employ both ER and UML class diagrams to represent the same database (De Lucia et al 2008b). Clearly, this can be a problem during the evolution of the data models since more effort is required to maintain the models and their implementation up-to-date.…”

“…We also report and discuss the results of our previous controlled experiments (De Lucia et al 2008b, c) to have a wide comparison of ER and UML class diagrams during comprehension, maintenance, and verification activities. We focus the attention only on these three activities, since they correspond to typical expectations of people using these two notations to represent conceptual data models.…”

“…In particular, the higher abstraction level of models should help to understand a system, modify it, and avoid defects in the early stages of development (Briand et al 2005). Thus, the specific contributions of this paper with respect to (De Lucia et al 2008b, c) are represented by a complete empirical comparison of the support given by UML class diagrams during comprehension, maintenance, and verification activities from the perspective of business analysts and customers with respect to ER diagrams. Indeed, our conjecture is that UML class diagrams are easier to understand and maintain than ER diagrams due to their more concise graphical notation.…”

“…The results showed that using UML class diagrams subjects achieved significantly better comprehension levels in both the experiments. In De Lucia et al (2008b) the two notations were compared during activities aimed at comprehending the change to perform to meet a change request. The results demonstrated that in this case the two notations provide the same support.…”