In this paper we present LEARN-SQL, a system conforming to the IMS QTI specification that allows on-line learning and assessment of students on SQL skills in an automatic, interactive, informative, scalable and extensible manner.
Abstract:The validation and the verification of conceptual schemas have attracted a lot of interest during the last years, and several tools have been developed to automate this process as much as possible. This is achieved, in general, by assessing whether the schema satisfies different kinds of desirable properties which ensure that the schema is correct. In this paper we describe AuRUS, a tool we have developed to analyze UML/OCL conceptual schemas and to explain their (in)correctness. When a property is satisfied, AuRUS provides a sample instantiation of the schema showing a particular situation where the property holds. When it is not, AuRUS provides an explanation for such unsatisfiability, i.e., a set of integrity constraints which is in contradiction with the property.
We extend here the Internal Events Method for change computation. This method derives a set of rules that incrementally compute the changes induced by an update, taking into account rwt only the update, but also the concept of event and the knowledge provided by the primary key integrity constraints. In this paper we further develop this idea by considering four additional integrity constraints: inclusion dependencies, exclusion dependencies, alternate keys and referential integrity constraints. We show that the knowledge provided by these integrity constraints allows us to save redundant checks and in some cases to remove whole rules. Thus, we obtain a signijicant improvement in performance. To the best of our knowledge there is no method for change computation with this capability
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