Therefore, index structures can easily be used in queries. A typical example is a join cursor which consumes the outputs of two underlying cursors. Most of our work is however not dedicated to the area of relational databases, but mainly refers to ...

FACT (Fast and ACcuraTe) is a query processing system aimed at providing users with facilities so that they can get the query results from the Web in a database-like fashion. The system takes user queries in the form of keywords (free text) and returns ...

Clustering is one of the most important tasks performed in Data Mining applications. This paper presents an efficient SQL implementation of the EM algorithm to perform clustering in very large databases. Our version can effectively handle high ...

The DataLinks technology developed at IBM Almaden Research Center and now available in DB2 UDB 5.2 introduces a new data type called DATALINK for a database to reference and manage files stored external to the database. An external file is put under a ...

Materialized views (or Automatic Summary Tables—ASTs) are commonly used to improve the performance of aggregation queries by orders of magnitude. In contrast to regular tables, ASTs are synchronized by the database system. In this paper, we present ...

Testing an SQL database system by running large sets of deterministic or stochastic SQL statements is common practice in commercial database development. However, code defects often remain undetected as the query optimizer's choice of an execution plan ...

In large data warehousing environments, it is often advantageous to provide fast, approximate answers to complex decision support queries using precomputed summary statistics, such as samples. Decision support queries routinely segment the data into ...

Finding approximate answers to multi-dimensional range queries over real valued attributes has significant applications in data exploration and database query optimization. In this paper we consider the following problem: given a table of d attributes ...

This paper describes the Onion technique, a special indexing structure for linear optimization queries. Linear optimization queries ask for top-N records subject to the maximization or minimization of linearly weighted sum of record attribute values. ...

A spatial distance join is a relatively new type of operation introduced for spatial and multimedia database applications. Additional requirements for ranking and stopping cardinality are often combined with the spatial distance join in on-line query ...

The advent of the World Wide Web has created an explosion in the available on-line information. As the range of potential choices expand, the time and effort required to sort through them also expands. We propose a formal framework for expressing and ...

LH*_RS is a new high-availability Scalable Distributed Data Structure (SDDS). The data storage scheme and the search performance of LH*_RS are basically these of LH*. LH*_RS manages in addition the parity information to tolerate the unavailability of k ⪈ 1 ...

We present MOCHA, a new self-extensible database middleware system designed to interconnect distributed data sources. MOCHA is designed to scale to large environments and is based on the idea that some of the user-defined functionality in the system ...