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DBPL
1995
Springer

On Impossibility of Decremental Recomputation of Recursive Queries in Relational Calculus and SQL

11 years 5 months ago
On Impossibility of Decremental Recomputation of Recursive Queries in Relational Calculus and SQL
We study the problem of maintaining recursively-de ned views, such as the transitive closure of a relation, in traditional relational languages that do not have recursion mechanisms. In particular, we show that the transitive closure cannot be maintained in relational calculus under deletion of edges. We use new proof techniques to show this result. These proof techniques generalize to other languages, for example, to the language for nested relations that also contains a number of aggregate functions. Such a language is considered in this paper as a theoretical reconstruction of SQL. Our proof techniques also generalize to other recursive queries. Consequently, we show that a number of recursive queries cannot be maintained in an SQL-like language. We show that this continues to be true in the presence of certain auxiliary relations. We also relate the complexity of updating transitive closure to that of updating the samegeneration query and show that the latter is strictly harder th...
Guozhu Dong, Leonid Libkin, Limsoon Wong
Added 26 Aug 2010
Updated 26 Aug 2010
Type Conference
Year 1995
Where DBPL
Authors Guozhu Dong, Leonid Libkin, Limsoon Wong
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