منابع مشابه
Flexible view update
As uninstantiated windows onto a relational database, views are modified only when the intended update can be realized by updates against the underlying database. Such a conventional restriction can, and must, be relaxed when some relations, as collections of predicates, are composed of both basic and derived facts. Therefore, this paper presents an extended formulation for the problem of view ...
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OBJECTIVE An update on ureteroscopy with focus on current technology and newer instrumentation is presented. METHODS A literature search through Medline-indexed journals as well as personal comments are included in this review. Topics such as new semirigid and flexible ureteroscopes, lasers, ureteral access sheats, wires and stone extraction devices are outlined. RESULTS Thanks to the conti...
متن کاملHypertext view update problem
A hypertext view is a derived hypertext for a given database. We are interested in providing a mechanism of translating hypertext view update operations to appropriate data manipulation operations in database. However, given a hypertext view update operation, we cannot always uniquely determine what needs to be done in terms of database operations to perform the intended hypertext view update o...
متن کاملTiling the view update problem
The paper describes a novel algebraic framework for specifying backward translations of view updates. It is based on diagram operations and can be considered an essential generalization of dynamic views (known in the literature since the eighties). A distinctive feature of the framework is that both view and update mappings are first class citizens and explicitly occur in the arity shape of the...
متن کاملThe View Update Problem Revisited
In this paper, we revisit the view update problem in a relational setting and propose a framework based on the notion of determinacy under constraints. Within such a framework, we characterise when a view mapping is invertible, establishing that this is the case precisely when each database symbol has an exact rewriting in terms of the view symbols under the given constraints, and we provide a ...
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ژورنال
عنوان ژورنال: Information Sciences
سال: 1992
ISSN: 0020-0255
DOI: 10.1016/0020-0255(92)90063-e