UML consistency rules: a systematic mapping study

Context: The Unified Modeling Language (UML), with its 14

different diagram types, is the de-facto standard tool for objectoriented

modeling and documentation. Since the various UML

diagrams describe different aspects of one, and only one, software

under development, they are not independent but strongly depend

on each other in many ways. In other words, the UML diagrams

describing a software must be consistent. Inconsistencies between

these diagrams may be a source of the considerable increase of

faults in software systems. It is therefore paramount that these

inconsistencies be detected, analyzed and hopefully fixed.

Objective:

The aim of this article is to deliver a comprehensive

summary of UML consistency rules as they are described in the

literature to date to obtain an extensive and detailed overview of

the current research in this area.

Method:

We performed a Systematic Mapping Study by

following well-known guidelines. We selected 94 primary studies

from a search with seven search engines performed in December

2012.

Results:

Different results are worth mentioning. First it appears

that researchers tend to discuss very similar consistency rules,

over and over again. Most rules are horizontal (98.07%) and

syntactic (88.03%). The most used diagrams are the class diagram

(71.28%), the state machine diagram (42.55%) and the sequence

diagram (47.87%).

Conclusion:

The fact that many rules are duplicated in primary

studies confirms the need for a well accepted list of consistency

rules. This paper is a first step in this direction. Results indicate

that much more work is needed to develop consistency rules for

all 14 UML diagrams, in all dimensions of consistency (e.g.,

semantic and syntactic on the one hand, horizontal, vertical and

evolution on the other hand).