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We present incremental evaluation algorithms to compute changes to materialized views in relational and deductive database systems, in response to changes (insertions, deletions, and updates) to the relations. The view definitions can be in SQL or Datalog, and may use UNION, negation, aggregation (<italic>e.g.</italic> SUM, MIN), linear recursion, and(More)
At the heart of all OLAP or multidimensional data analysis applications is the ability to simultaneously aggregate across many sets of dimensions. Computing multidimensional aggregates is a performance bottleneck for these applications. This paper presents fast algorithms for computing a collection of group bys. We focus on a special case of the(More)
Constraints are a valuable tool for managing information across multiple databases, as well as for general purposes of assuring data integrity. However, efficient implementation of constraint checking is difficult. In this paper we explore techniques for assuring constraint satisfaction without performing a complete evaluation of the constraints. We(More)
The Bulletin of the Technical Committee on Data Engineering is published quarterly and is distributed to all TC members. Its scope includes the design, implementation, modelling, theory and application of database systems and their technology. Letters, conference information, and news should be sent to the Editor-in-Chief. Papers for each issue are(More)
In this paper we i n troduce generalized p r o-jections GPs, an extension of duplicate-eliminating projections, that capture aggre-gations, groupbys, duplicate-eliminating projections distinct, and duplicate-preserving projections in a common uniied framework. Using GPs w e extend well known and simple algorithms for SQL queries that use distinct(More)
A data warehouse stores materialized views over data from one or more sources in order to provide fast access to the integrated data, regardless of the availability of the data sources. Warehouse views need to be maintained in response to changes to the base data in the sources. Except for very simple views, maintaining a warehouse view requires access to(More)
Integration of data from multiple databases is an important problem. We consider a model for data integration wherein data from multiple databases is combined into an integrated view that is materialized and stored in a database. All queries on the view are then answered directly from the view, without having to go to the diierent databases. Such a model is(More)
Wrappers provide access to heterogeneous information sources by converting application queries into source speciic queries or commands. In this paper we present a wrapper implementation toolkit that facilitates rapid development of wrappers. We focus on the query translation component of the toolkit, called the converter. The converter takes as input a(More)
We present an incremental evaluation algorithm for materialized views in relational and deductive database systems. The algorithm computes, in an incremental fashion, the changes to the materialized view in response to changes (insertions, deletions, and updates) to the base relations. The view may be deened in SQL or in Datalog, and may use UNION ,(More)