XSEarch: A Semantic Search Engine for XML
Inferring a Tree from Lowest Common Ancestors with an Application to the Optimization of Relational Expressions
- A. Aho, Y. Sagiv, T. G. Szymanski, J. Ullman
- Computer ScienceSIAM journal on computing (Print)
- 1 August 1981
We present an algorithm for constructing a tree to satisfy a set of lineage constraints on common ancestors. We then apply this algorithm to synthesize a relational algebra expression from a simple…
The TSIMMIS Approach to Mediation: Data Models and Languages
- H. Garcia-Molina, Y. Papakonstantinou, J. Widom
- Computer ScienceJournal of Intelligence and Information Systems
- 31 March 1997
TSIMMIS—The Stanford-IBM Manager of Multiple Information sources offers a datamodel and a common query language that are designed to support the combining of information from many different sources.
Equivalences Among Relational Expressions with the Union and Difference Operators
It is shown that containment of tableaux is a necessary step in testing equivalence of queries with union and difference, and the containment problem is shown to be NP-complete even for tableaux that correspond to expressions with only one project and several join operators.
Keyword proximity search in complex data graphs
This paper presents an engine that generates all the answers with provable guarantees for keyword search over data graphs and presents a novel approach for implementing rankers destined for eliminating redundancy.
Answering Queries Using Views.
Querying object-oriented databases
This paper presents a new query language, henceforth referred to as XSQL, that incorporates novelties not found in earlier languages and is easier to use and it has more expressive power than previous languages.
Magic sets and other strange ways to implement logic programs (extended abstract)
- F. Bancilhon, D. Maier, Y. Sagiv, J. Ullman
- Computer ScienceACM SIGACT-SIGMOD-SIGART Symposium on Principles…
- 1 June 1985
Several methods for implementing database queries expressed as logical rules, including a general algorithm for rewriting logical rules so that they may be implemented bottomUP (= forward chaining) in a way that cuts down on the irrelevant facts that are generated.
Testing implications of data dependencies
The chase can be used to test equivalence of database schemes and as part of the test of whether the relation schemes in a database scheme are independent components.
Monotonic aggregation in deductive databases
- K. A. Ross, Y. Sagiv
- Computer Science, EconomicsACM SIGACT-SIGMOD-SIGART Symposium on Principles…
- 1 July 1992
This work forms a minimal model of a program component including aggregate operators, rather than insisting that the aggregate apply to atoms that have been fully determined, or that aggregate functions are rewritten in terms of negation.