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17
Taxonomy of xml schema languages using formal language theory
 EXTREME MARKUP LANGUAGES
, 2001
"... On the basis of regular tree grammars, we present a formal framework for XML schema languages. This framework helps to describe, compare, and implement such schema languages in a rigorous manner. Our main results are as follows: (1) a simple framework to study three classes of tree languages (local, ..."
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Cited by 206 (6 self)
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On the basis of regular tree grammars, we present a formal framework for XML schema languages. This framework helps to describe, compare, and implement such schema languages in a rigorous manner. Our main results are as follows: (1) a simple framework to study three classes of tree languages (local, singletype, and regular); (2) classification and comparison of schema languages (DTD, W3C XML Schema, and RELAX NG) based on these classes; (3) efficient document validation algorithms for these classes; and (4) other grammatical concepts and advanced validation algorithms relevant to an XML model (e.g., binarization, derivativebased validation).
XML constraints: Specification, analysis, and applications
 In Proc. DEXA
, 2005
"... This paper reviews the recent developments in specification languages, static and runtime analyses as well as applications of integrity constraints for XML. 1 ..."
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Cited by 15 (0 self)
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This paper reviews the recent developments in specification languages, static and runtime analyses as well as applications of integrity constraints for XML. 1
Firstorder and temporal logics for nested words
 In LICS 2007
"... Nested words are a structured model of execution paths in procedural programs, reflecting their call and return nesting structure. Finite nested words also capture the structure of parse trees and other treestructured data, such as XML. We provide new temporal logics for finite and infinite nested ..."
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Cited by 14 (3 self)
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Nested words are a structured model of execution paths in procedural programs, reflecting their call and return nesting structure. Finite nested words also capture the structure of parse trees and other treestructured data, such as XML. We provide new temporal logics for finite and infinite nested words, which are natural extensions of LTL, and prove that these logics are firstorder expressivelycomplete. One of them is based on adding a ”within” modality, evaluating a formula on a subword, to a logic CaRet previously studied in the context of verifying properties of recursive state machines. The other logic is based on the notion of a summary path that combines the linear and nesting structures. For that logic, both modelchecking and satisfiability are shown to be EXPTIMEcomplete. Finally, we prove that firstorder logic over nested words has the threevariable property, and we present a temporal logic for nested words which is complete for the twovariable fragment of firstorder. 1
ValiditySensitive Querying of XML Databases
 In EDBT Workshops (dataX
, 2006
"... Abstract. We consider the problem of querying XML documents which are not valid with respect to given DTDs. We propose a framework for measuring the invalidity of XML documents and compactly representing minimal repairing scenarios. Furthermore, we present a validitysensitive method of querying XML ..."
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Cited by 8 (3 self)
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Abstract. We consider the problem of querying XML documents which are not valid with respect to given DTDs. We propose a framework for measuring the invalidity of XML documents and compactly representing minimal repairing scenarios. Furthermore, we present a validitysensitive method of querying XML documents, which extracts more information from invalid XML documents than does the standard query evaluation. Finally, we provide experimental results which validate our approach. 1
Combining temporal logics for querying XML documents
 In International Conference on Database Theory
, 2006
"... Abstract. Close relationships between XML navigation and temporal logics have been discovered recently, in particular between logics LTL and CTL ⋆ and XPath navigation, and between the µcalculus and navigation based on regular expressions. This opened up the possibility of bringing modelchecking t ..."
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Cited by 8 (2 self)
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Abstract. Close relationships between XML navigation and temporal logics have been discovered recently, in particular between logics LTL and CTL ⋆ and XPath navigation, and between the µcalculus and navigation based on regular expressions. This opened up the possibility of bringing modelchecking techniques into the field of XML, as documents are naturally represented as labeled transition systems. Most known results of this kind, however, are limited to Boolean or unary queries, which are not always sufficient for complex querying tasks. Here we present a technique for combining temporal logics to capture nary XML queries expressible in two yardstick languages: FO and MSO. We show that by adding simple terms to the language, and combining a temporal logic for words together with a temporal logic for unary tree queries, one obtains logics that select arbitrary tuples of elements, and can thus be used as building blocks in complex query languages. We present general results on the expressiveness of such temporal logics, study their modelchecking properties, and relate them to some common XML querying tasks. 1
Bisimulation Minimisation of Weighted Automata on Unranked Trees
, 2008
"... Two examples of automatatheoretic models for the validation of xml documents against userde ned schema are the stepwise unranked tree automaton (suta) and the parallel unranked tree automaton (puta). By adding a weight, taken from some semiring, to every transition we generalise these two qualitat ..."
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Cited by 4 (1 self)
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Two examples of automatatheoretic models for the validation of xml documents against userde ned schema are the stepwise unranked tree automaton (suta) and the parallel unranked tree automaton (puta). By adding a weight, taken from some semiring, to every transition we generalise these two qualitative automata models to quantitative models, thereby obtaining weighted stepwise unranked tree automata (wsuta) and weighted parallel unranked tree automata (wputa); the qualitative automata models are reobtained by choosing the Boolean semiring. We deal with the minimisation problem of wsuta and wputa by using (forward and backward) bisimulations and we prove the following results: (1) for every wsuta an equivalent forward (resp. backward) bisimulation minimal wsuta can be computed in time O(mn) where n is the number of states and m is the number of transitions of the given wsuta; (2) the same result is proved for wputa instead of wsuta; (3) if the semiring is additive cancellative or the Boolean semiring, then the bound can be improved to O(m log n) for both wsuta and wputa; (4) for every deterministic puta we can compute a minimal equivalent deterministic puta in time O(m log n); (5) the automata models wsuta, wputa, and weighted unranked tree automaton have the same computational power.
On the Equivalence between FDs in XML and FDs in Relations
"... the date of receipt and acceptance should be inserted later Abstract With the growing use of the eXtensible Markup Language (XML) in database technology as a format for the permanent storage of data, the topic functional dependencies in XML (XFDs) has assumed increased importance because of its cent ..."
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Cited by 4 (1 self)
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the date of receipt and acceptance should be inserted later Abstract With the growing use of the eXtensible Markup Language (XML) in database technology as a format for the permanent storage of data, the topic functional dependencies in XML (XFDs) has assumed increased importance because of its central role in database design. Recently, two different approaches have been proposed for defining an XFD. The first uses the concept of a ’tree tuple’, whereas the second uses the concept of a ’closest node’. In general, the two approaches are not comparable, but are comparable when a Document Type Definition (DTD) is present and there is no missing information in the XML document. The first contribution of this article shows that when the two XFD definitions are comparable, the definitions are equivalent, and so there is essentially a common definition of an XFD in complete XML documents. The second contribution is to provide justification for the definition of a ’closest node’ XFD. We show that if a complete flat relation is mapped to an XML document by an arbitrary sequence of nest operations, the XML document satisfies a ’closest node ’ XFD if and only if the relation satisfies the corresponding functional dependency (FD). The class of XML documents generated in this
Tractable XML Data Exchange via Relations
, 2010
"... We consider data exchange for XML documents: given source and target schemas, a mapping between them, and a document conforming to the source schema, construct a target document and answer target queries in a way that is consistent with source information. The problem has primarily been studied in t ..."
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Cited by 2 (0 self)
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We consider data exchange for XML documents: given source and target schemas, a mapping between them, and a document conforming to the source schema, construct a target document and answer target queries in a way that is consistent with source information. The problem has primarily been studied in the relational context, in which dataexchange systems have also been built. Since many XML documents are stored in relations, it is natural to consider using a relational system for XML data exchange. However, there is a complexity mismatch between query answering in relational and XML data exchange, which indicates that restrictions have to be imposed on XML schemas and mappings, and on XML shredding schemes, to make the use of relational systems possible. We isolate a set of five requirements that must be fulfilled in order to have a faithful representation of the XML dataexchange problem by a relational translation. We then demonstrate that these requirements naturally suggest the inlining technique for dataexchange tasks. Our key contribution is to provide shredding algorithms for schemas, documents, mappings and queries, and demonstrate that they enable us to correctly perform XML dataexchange tasks using a relational system.
XML Transformation Language Based on Monadic Secondorder Logic
"... Abstract. Although monadic secondorder logic (MSO) has been a foundation of XML queries, little work has attempted to take MSO formulae themselves as a programming construct. Indeed, MSO can express (1) all regular queries, (2) deep matching without explicit recursion, (3) queries that “don’t care ..."
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Cited by 2 (2 self)
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Abstract. Although monadic secondorder logic (MSO) has been a foundation of XML queries, little work has attempted to take MSO formulae themselves as a programming construct. Indeed, MSO can express (1) all regular queries, (2) deep matching without explicit recursion, (3) queries that “don’t care ” unmentioned nodes, and (4) nary queries for locating ntuples of nodes. While previous frameworks for subtree extraction (path expressions, pattern matches, etc.) each have some of these properties, none satisfies all. In this work, we have designed and implemented a practical XML transformation language, MTran, fully exploiting MSO’s expressiveness. Based on XSLTlike “selectandtransform” paradigm, we design transformation templates specially suitable for expressing structurepreserving transformation, eliminating the need for explicit recursive calls. Also, we allow nesting of templates for making use of an nary query that depends on previously selected n − 1 nodes. For the implementation, we have developed an efficient evaluation strategy for nary MSO queries, consisting of (a) an exploitation of MONA system for the translation from MSO to tree automata and (b) a linear time query evaluation algorithm for tree automata. The latter is similar to FlumFrickGrohe algorithm locating ntuples of sets of nodes, except that our query is specialized to querying tuples of nodes and employs partially lazy set operations for attaining a simpler implementation with a fewer number of tree traversals. Our preliminary experiments confirm that our strategy yields a practical performance. 1
Weighted logics for XML
, 2007
"... Abstract: We define a weighted monadic second order logic for XMLdocuments (weighted uMSOlogic), viewed as unranked trees. Such a logic allows us to pose quantitative queries to XMLdatabases. Also we define the concept of unranked weighted tree automata and prove that, for every commutative semir ..."
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Cited by 1 (0 self)
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Abstract: We define a weighted monadic second order logic for XMLdocuments (weighted uMSOlogic), viewed as unranked trees. Such a logic allows us to pose quantitative queries to XMLdatabases. Also we define the concept of unranked weighted tree automata and prove that, for every commutative semiring K, they have the same expressive power as (1) restricted weighted uMSOlogic, (2) almost existential weighted uMSOlogic whenever the additive monoid of K is locally finite, (3) (unrestricted) weighted uMSOlogic whenever K is locally finite. Moreover, if K is a computable field, then the equivalence of any two sentences of restricted weighted uMSOlogic is decidable and there is an effective procedure to construct the automaton from the sentence. 1