EquiX---A Search and Query Language for XML

EquiX is a search language for XML that combines the power of querying with the simplicity of searching. Requirements for such languages are discussed and it is shown that EquiX meets the necessary criteria. Both a graphical abstract syntax and a formal concrete syntax are presented for EquiX queries. In addition, the semantics is defined and an evaluation algorithm is presented. The evaluation algorithm is polynomial under combined complexity. EquiX combines pattern matching, quantification and logical expressions to query both the data and meta-data of XML documents. The result of a query in EquiX is a set of XML documents. A DTD describing the result documents is derived automatically from the query.Comment: technical report of Hebrew University Jerusalem Israe

Querying parse trees of stochastic context-free grammars

ABSTRACT Stochastic context-free grammars (SCFGs) have long been recognized as useful for a large variety of tasks including natural language processing, morphological parsing, speech recognition, information extraction, Web-page wrapping and even analysis of RNA. A string and an SCFG jointly represent a probabilistic interpretation of the meaning of the string, in the form of a (possibly infinite) probability space of parse trees. The problem of evaluating a query over this probability space is considered under the conventional semantics of querying a probabilistic database. For general SCFGs, extremely simple queries may have results that include irrational probabilities. But, for a large subclass of SCFGs (that includes all the standard studied subclasses of SCFGs) and the language of tree-pattern queries with projection (and child/descendant edges), it is shown that query results have rational probabilities with a polynomialsize bit representation and, more importantly, an efficient query-evaluation algorithm is presented

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

User accessibility of web data

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Querying RDBMS using Natural Language

It is often challenging to specify queries against a relational database since SQL requires its users to know the exact schema of the database, the roles of various entities in a query, and the precise join paths to be followed. On the other hand, keyword search is unable to express many desired query semantics. In the real world, people ask questions in natural language, such as English. Theoretically, natural language interfaces for databases (NLIDBs) have many advantages over other widely accepted query interfaces (keyword-based search, form-based interface, and visual query builder). For example, a typical NLIDB would enable naive users to specify complex, ad-hoc query intent without training. Not surprisingly, an NLIDB is regarded by many as the ultimate goal. Despite these advantages, in real world applications, NLIDBs have not been widely adopted. In this dissertation, we investigate the construction of NLIDBs, specifically from the following three aspects: A natural language query is inherently ambiguous and some ambiguities may be too hard for computers to resolve. Can a system collaborate with users to achieve satisfactory reliability without burdening the user too much? The interpretation process can be considered as a mapping from a natural language query to the correct point in the semantic coverage of the NLIDB. Can the mapping process get easier by carefully defining the semantic coverage? Can an NLIDB work when no training examples are available, collect the user behavior data as the training examples and improve itself from real usage? In this dissertation, we provide affirmative answers to the above questions in the form of new query mechanism designed, techniques provided and systems constructed.PHDComputer Science & EngineeringUniversity of Michigan, Horace H. Rackham School of Graduate Studieshttps://deepblue.lib.umich.edu/bitstream/2027.42/138709/1/lifei_1.pd

Equix - A Search and Query Language for XML

status: publishe

EquiX : A Search and Query Language for XML

Special Issue on XMLstatus: publishe

EquiX—a search and query language for XML

EquiX is a search language for XML that combines the power of querying with the simplicity of searching. Requirements for such languages are discussed and it is shown that EquiX meets the necessary criteria. Both a graphical abstract syntax and a formal concrete syntax are presented for EquiX queries. In addition, the semantics is defined and an evaluation algorithm is presented. The evaluation algorithm is polynomial under combined complexity. EquiX combines pattern matching, quantification and logical expressions to query both the data and meta-data of XML documents. The result of a query in EquiX is a set of XML documents. A DTD describing the result documents is derived automatically from the query.