2 resultados para data movement problem

em Lume - Repositório Digital da Universidade Federal do Rio Grande do Sul


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This thesis addresses the problem of the academic identity of the area traditionally referred to as physical education. The study is a critical examination of the argu ments for the justi cation of this area as an autonomous branch of knowledge. The investigation concentrates on a selected number of arguments. The data collection comprised articles books and proceedings of conferences. The preliminary assessment of these materials resulted in a classi cation of the arguments into three groups. The rst group comprises the arguments in favour of physical education as an academic discipline. The second includes the arguments supporting a science of sport. The third consists of the arguments in favour of to a eld of human movement study. The examination of these arguments produced the following results. (a) The area of physical education does not satisfy the conditions presupposed by the de nition of academic discipline. This is so because the area does not form an integrated system of scienti c theories. (b) The same di culty emerges from the examination of the ar guments for sport science. There is no science of sport because there is no integrated system of scienti c theories related to sport. (c) The arguments in favour of a eld of study yielded more productive results. However di culties arise from the de nition of human movement. The analysis of this concept showed that its limits are not well demarcated. This makes it problematic to take human movement as the focus of a eld of studies. These aspects led to the conclusion that such things as an academic discipline of physical education sport science and eld of human movement studies do not exist. At least there are not such things in the sense of autonomous branches of knowledge. This does not imply that a more integrated inquiry based on several disciplines is not possible and desirable. This would enable someone entering phys ical education to nd a more organised structure of knowledge with some generally accepted problem situations procedures and theories on which to base professional practice.

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XML has become an important medium for data exchange, and is frequently used as an interface to - i.e. a view of - a relational database. Although lots of work have been done on querying relational databases through XML views, the problem of updating relational databases through XML views has not received much attention. In this work, we give the rst steps towards solving this problem. Using query trees to capture the notions of selection, projection, nesting, grouping, and heterogeneous sets found throughout most XML query languages, we show how XML views expressed using query trees can be mapped to a set of corresponding relational views. Thus, we transform the problem of updating relational databases through XML views into a classical problem of updating relational databases through relational views. We then show how updates on the XML view are mapped to updates on the corresponding relational views. Existing work on updating relational views can then be leveraged to determine whether or not the relational views are updatable with respect to the relational updates, and if so, to translate the updates to the underlying relational database. Since query trees are a formal characterization of view de nition queries, they are not well suited for end-users. We then investigate how a subset of XQuery can be used as a top level language, and show how query trees can be used as an intermediate representation of view de nitions expressed in this subset.