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» Some Properties of Query Languages for Bags
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DBPL
1993
Springer
141views Database» more  DBPL 1993»
9 years 5 months ago
Some Properties of Query Languages for Bags
In this paper we study the expressive power of query languages for nested bags. We de ne the ambient bag language by generalizing the constructs of the relational language of Brea...
Leonid Libkin, Limsoon Wong
VLDB
1991
ACM
190views Database» more  VLDB 1991»
9 years 4 months ago
Algebraic Properties of Bag Data Types
We explore the implications of supporting bags (i.e. multisets) in a data model and associated query language, and present some formal results concerned with the algebraic propert...
Joseph Albert
ICDT
1997
ACM
138views Database» more  ICDT 1997»
9 years 5 months ago
Tractable Iteration Mechanisms for Bag Languages
Abstract. The goal of this paper is to study tractable iteration mechanisms for bags. The presence of duplicates in bags prevents iteration mechanisms developed in the context of s...
Latha S. Colby, Leonid Libkin
SDB
1995
178views Database» more  SDB 1995»
9 years 4 months ago
A Semantics-based Approach to Design of Query Languages for Partial Information
Most of work on partial information in databases asks which operations of standard languages, like relational algebra, can still be performed correctly in the presence of nulls. In...
Leonid Libkin
CORR
2011
Springer
135views Education» more  CORR 2011»
8 years 5 months ago
On the Limitations of Provenance for Queries With Difference
The annotation of the results of database transformations was shown to be very effective for various applications. Until recently, most works in this context focused on positive q...
Yael Amsterdamer, Daniel Deutch, Val Tannen
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