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This paper argues that the treatment of incomplete information in conventional database systems is inadequate. It is not possible for users to formulate queries which clearly state what it is they want to know and the answers to queries are often misleading. These problems can be remedied by the use of modal logic which allows questions to be asked about what might be true and what must be true, rather...
This paper introduces a Temporal Functional Database Language (TFDL), which realizes an event oriented approach to historical database modeling. According to this approach, the events that occur in an evolving system is the fundamental information which should be recorded. The time series of the system states is secondary information in the sense that it can be derived from the occurred events.
This paper presents and discusses a radically different approach to multi-dimensional indexing based on the concept of the space-filling curve. It reports the novel algorithms which had to be developed to create the first actual implementation of a system based on this approach, on some comparative performance tests, and on its actual use within the TriStarp Group at Birkbeck to provide a Triple Store...
We describe in brief a lazy functional database language Relief, which supports an entity-function model and provides for update and the input of data by means of functions with side-effects. An eager let construct is used within the lazy graph reduction mechanism to sequence the effects. To redress the loss of referential transparency we have implemented an effects checker which can identify referentially...
This paper introduces a new approach to incorporating the temporal dimension in database systems. Instead of introducing time as an attribute in a conventional state database the paper proposes that state databases are derivatives from event databases which are regarded as fundamental. A data modelling approach is introduced together with a realization in terms of a Temporal Functional Database Language...
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