Unbounded data model verification using SMT solvers

Abstract

The growing influence of web applications in every aspect of society makes their dependability an immense concern. A fundamental building block of web applications that use the Model-View-Controller (MVC) pattern is the data model, which specifies the object classes and the relations among them. We present an approach for unbounded, automated verification of data models that 1) extracts a formal data model from an Object Relational Mapping, 2) converts verification queries about the data model to queries about the satisfiability of formulas in the theory of uninterpreted functions, and 3) uses a Satisfiability Modulo Theories (SMT) solver to check the satisfiability of the resulting formulas. We implemented this approach and applied it to five opensource Rails applications. Our results demonstrate that the proposed approach is feasible, and is more efficient than SAT-based bounded verification.

Weaving True-Concurrent Aspects Using Constraint Solvers

“…Table 2 shows that when messages are structured further through combined fragments, the performance of Alloy is strongly affected. This study confirms the conclusion of [13], i.e., that Alloy's performance is affected by the number of variable clauses. Indeed, with an increasing number of combined fragments the performance of Alloy becomes very slow.…”

“…On the other hand, Z3 showed good performance throughout most of the experiment and increasing the number of messages did not produce any significant effect on its performance (less than 1 minute on average -see Figure 7). According to Nijjar and Bultan [13], there are several reasons that explain why Z3 performs better than Alloy. First, Z3 uses many heuristics to eliminate quantifiers in formulas.…”

“…In recent work [9], [10], we presented a fully automated approach for the composition of sequence diagrams making use of the constraint solver Alloy [11]. Moreover, a well known problem of how poor tool performance impacts on their applicability for large and complex models is discussed for instance in [12], [13]. As a result, this paper investigates an alternative composition method in the context of AOM weaving through the use of Z3 [14].…”

An integrated data model verifier with property templates

“…To facilitate this process, we developed a set of property templates. These templates characterize the most common properties we observed in our earlier research on data model verification [10], [11]. These templates can easily be instantiated for different classes and relations by the user.…”

“…Our tool combines three different variants of this framework. The first two are SAT-based bounded verification and Satisfiability Modula Theories (SMT)-based unbounded verification from our earlier work [10], [11]. In this paper, we add another unbounded verification approach based on First Order Logic (FOL) and a FOL theorem prover.…”