STRUCTURED DOCUMENT LOGIC

This paper describes some practical and theoretical foundations of Structured Document Logic (SDL), which is a logical methodology for analyzing properties of Web documents, like XML or HTML. SDL can make benefits in searching of HTML pages, or in defining filters for web documents. Both syntax and semantics of SDL are described, and an efficient evaluation algorithm is also introduced

Expressiveness and complexity of graph logic

We investigate the complexity and expressive power of the spatial logic for querying graphs introduced by Cardelli, Gardner and Ghelli (ICALP 2002).We show that the model-checking complexity of versions of this logic with and without recursion is PSPACE-complete. In terms of expressive power, the version without recursion is a fragment of the monadic second-order logic of graphs and we show that it can express complete problems at every level of the polynomial hierarchy. We also show that it can define all regular languages, when interpretation is restricted to strings. The expressive power of the logic with recursion is much greater as it can express properties that are PSPACE-complete and therefore unlikely to be definable in second-order logic

Web and Semantic Web Query Languages

A number of techniques have been developed to facilitate powerful data retrieval on the Web and Semantic Web. Three categories of Web query languages can be distinguished, according to the format of the data they can retrieve: XML, RDF and Topic Maps. This article introduces the spectrum of languages falling into these categories and summarises their salient aspects. The languages are introduced using common sample data and query types. Key aspects of the query languages considered are stressed in a conclusion

Expressiveness improvements of OutSystems DSL query primitives

Dissertação para obtenção do Grau de Mestre em Engenharia InformáticaIn the ever more competitive market, companies are forced to reduce their operational costs and innovate. In order to do that, some companies successfully adopted new approaches, some of them using domain specific languages (DSL), building their entire system and all the respective layers in less time and more focused in their business. Frequently, the application business layer interacts with the data layer through SQL queries, in order to obtain or modify data. There are some products in the market that try to make life easier for developers, allowing them to get the data using the features of visual query builders, also available in standard SQL. However, it is not expectable that every possible query can be written through these visual query builders, which leads us to the following questions "What should and what can easily be supported by visual query builders?". These questions are relevant in order to help improving the experience of developers and save them time. This work aims to study and analyse techniques that help detecting patterns in structured data and, afterwards, propose a suitable way to view and manage the visualization of the occurrence of such detected patterns. In order to help identify the most frequent patterns and thus contribute to solve the above questions, with this conjunction of topics we expect to provide a way to improve the experience of understanding a large amount of data in a particular context. Once understood some patterns that could be present in the data and their importance, we are ready to propose a new model in the context of OutSystems Agile PlatformTM, in terms of their visual query builder, aiming to increase its value, improve its expressiveness and offer a powerful visual way to build queries

Logic and Automata

Mathematical logic and automata theory are two scientific disciplines with a fundamentally close relationship. The authors of Logic and Automata take the occasion of the sixtieth birthday of Wolfgang Thomas to present a tour d'horizon of automata theory and logic. The twenty papers in this volume cover many different facets of logic and automata theory, emphasizing the connections to other disciplines such as games, algorithms, and semigroup theory, as well as discussing current challenges in the field

The Query Language TQL

This work presents the query language TQL, a query language for semistructured data, that can be used to query XML files. TQL substitutes the standard path-based pattern-matching mechanism with a logic-based mechanism, where the programmer specifies the properties of the pieces of data she is trying to extract. As a result, TQL queries are more `declarative', or less `operational', than queries in comparable languages. This feature makes some queries easier to express, and should allow the adoption of better optimization techniques. Through a set of examples, we show that the range of queries that can be declaratively expressed in TQL is quite wide. The implementation of TQL binding mechanism requires the adoption of non-standard techniques, and some of its aspects are still open. In this paper we implicitly report about the current status of the implementation by writing all queries using the version of TQL that has been implemented, and that can be freely downloaded from //tql.di.unipi.it/tql

The Query Language TQL Demo Presentation

This work presents the query language TQL, a query language for semistructured data, that can be used to query XML files. TQL substitutes the standard path-based patternmatching mechanism with a logic-based mechanism, where the programmer specifies the properties of the pieces of data he is trying to extract. As a result, TQL queries are more ‘declarative’, or less ‘operational’, than queries in comparable languages. This feature makes some queries easier to express, and should allow the adoption of better optimization techniques. Through a set of examples, which will presented at the SEBD demo, we show that the range of queries that can be declaratively expressed in TQL is quite wide.

The Query Language TQL Demo Presentation

This work presents the query language TQL, a query language for semistructured data, that can be used to query XML files. TQL substitute