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We are interested in the theoretical foundations of the optimization of conjunctive regular path queries (CRPQs). The basic problem here is deciding query containment both in the absence and presence of constraints. Containment without constraints for ...

The basic querying mechanism over semistructured data, namely regular path queries, asks for all pairs of objects that are connected by a path conforming to a regular expression. We consider conjunctive two-way regular path queries (C2RPQ_c's), which ...

In this paper we develop a new method for solving queries on semistructured data. The main idea is to see a database as a Kripke Transition System (a model) and a query as a formula of the temporal logic CTL. In this way, the retrieval of data ...

Commercial OLAP systems usually treat OLAP dimensions as static entities. In practice, dimension updates are often necessary in order to adapt the multidimensional database to changing requirements. In earlier work we proposed a temporal ...

To build the d-dimensional datacube, for on-line analytical processing, in the relational algebra, the database programming language must support a loop of d steps. Each step of the loop involves a different attribute of the data relation being cubed, ...

We present a simple Data Mining Logic (DML) that can express common data mining tasks, like "Find Boolean association rules" or "Find inclusion dependencies." At the center of the paper is the problem of characterizing DML queries that are amenable to ...

We study absolute and relative keys for XML, and investigate their associated decision problems. We argue that these keys are important to many forms of hierarchically structured data including XML documents. In contrast to other proposals of keys for ...

Querying XML has been the subject of much recent investigation. A formal bulk algebra is essential for applying database-style optimization to XML queries. We develop such an algebra, called TAX (Tree Algebra for XML), for manipulating XML data, modeled ...

We present XPathLog as a Datalog-style extension to XPath. The querying part extends XPath with binding variables to XML nodes that are "traversed" when evaluating an XPath expression. Data manipulation is done in a rule-based way. In contrast to other ...

We consider n-dimensional semi-algebraic spatial databases. We compute in first-order logic extended with a transitive closure operator, a linear spatial database which characterizes the semi-algebraic spatial database up to a homeomorphism. In this way,...

We address a fundamental question concerning spatio-temporal database systems: "What are exactly spatio-temporal queries?" We define spatio-temporal queries to be computable mappings that are also generic, meaning that the result of a query may only ...

Signatures are evolving profiles of entities extracted from streams of transactional data. For a stream of credit card transactions, for example, an entity might be a credit card number and a signature the average purchase amount. Signatures provide a ...

The core of a model theory for generic schema management is developed. This theory has two distinctive features: it applies to a variety of categories of schemas, and it applies to transformations of both the schema structure and its integrity ...

We present new algorithms for concurrent reading and updating of B^*-trees and binary search trees. Our algorithms are based on the well-known link technique, and improve previously proposed solutions in several respects. We prove formally that our ...

SQL4X, a powerful language for simultaneously querying both relational and XML databases is presented. Using SQL4X, one can create both relations and XML documents as query results. Thus, SQL4X can be thought of as an integration language. In order to ...

Perspective scenarios of e-commerce applications, in particular B2B applications, based on the exchange of XML documents open new research issues in the field of information systems and XML data management. In fact, information systems will have to ...

A key issue for active databases is optimising the execution event-condition-action rules. In this paper we show how partial evaluation provides a formal and general route to optimising such rules. We produce a specialised version of the rule execution ...

We propose a logical framework for describing, reasoning about, and simulating transaction models that relax some of the ACID (Atomicity-Consistency-Isolation-Durability) properties of classical transactions. Such extensions, usually called advanced ...