Developing a labelled object-relational constraint database architecture for the projection operator

Current relational databases have been developed in order to improve the handling of stored data, however, there are some types of information that have to be analysed for which no suitable tools are available. These new types of data can be represented and treated as constraints, allowing a set of data to be represented through equations, inequations and Boolean combinations of both. To this end, constraint databases were defined and some prototypes were developed. Since there are aspects that can be improved, we propose a new architecture called labelled object-relational constraint database (LORCDB). This provides more expressiveness, since the database is adapted in order to support more types of data, instead of the data having to be adapted to the database. In this paper, the projection operator of SQL is extended so that it works with linear and polynomial constraints and variables of constraints. In order to optimize query evaluation efficiency, some strategies and algorithms have been used to obtain an efficient query plan. Most work on constraint databases uses spatiotemporal data as case studies. However, this paper proposes model-based diagnosis since it is a highly potential research area, and model-based diagnosis permits more complicated queries than spatiotemporal examples. Our architecture permits the queries over constraints to be defined over different sets of variables by using symbolic substitution and elimination of variables.Ministerio de Ciencia y Tecnología DPI2006-15476-C02-0

Specification-enhanced execution

Thesis (S.M.)--Massachusetts Institute of Technology, Dept. of Electrical Engineering and Computer Science, 2010.Cataloged from PDF version of thesis.Includes bibliographical references (p. 54-57).Our goal is to provide a framework that allows the programmer to easily shift responsibility for certain aspects of the program execution to the runtime system. We present specification- enhanced execution, a programming and execution model that allows the programmer to describe certain aspects of program execution using high level specifications that the runtime is responsible for executing. With our approach, the programmer provides an implementation that covers certain aspects of program behavior and a set of specifications that cover other aspects of program behavior. We propose a runtime system that uses concolic (combined concrete and symbolic) execution to simultaneously execute all aspects of the program. We describe LogLog, a language we have designed for using this programming and runtime model. We present a case study applying this programing model to real-word data processing programs and demonstrate the feasibility of both the programming and runtime models.by Jean Yang.S.M