27 results on '"Liu, Chengfei"'
Search Results
2. Functional Dependencies, from Relational to XML
- Author
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Liu, Jixue, Vincent, Millist, Liu, Chengfei, Goos, Gerhard, editor, Hartmanis, Juris, editor, van Leeuwen, Jan, editor, Broy, Manfred, editor, and Zamulin, Alexandre V., editor
- Published
- 2003
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3. A Declarative Way of Extracting XML Data in XSL
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Liu, Jixue, Liu, Chengfei, Goos, Gerhard, editor, Hartmanis, Juris, editor, van Leeuwen, Jan, editor, Manolopoulos, Yannis, editor, and Návrat, Pavol, editor
- Published
- 2002
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4. ELCA evaluation for keyword search on probabilistic XML data
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Zhou, Rui, Liu, Chengfei, Li, Jianxin, and Yu, Jeffrey Xu
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- 2013
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5. Consistent query answers from virtually integrated XML data
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Tan, Zijing, Liu, Chengfei, Wang, Wei, and Shi, Baile
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XML ,Algorithm ,XML (Document markup language) -- Analysis ,Algorithms -- Analysis ,Computer science -- Analysis - Abstract
To link to full-text access for this article, visit this link: http://dx.doi.org/10.1016/j.jss.2010.08.018 Byline: Zijing Tan (a), Chengfei Liu (b), Wei Wang (a), Baile Shi (a) Keywords: XML; inconsistent; Query; Constraint Abstract: When data sources are virtually integrated, there is no common and centralized method to maintain global consistency, so inconsistencies with regard to global integrity constraints are very likely to occur. In this paper, we consider the problem of defining and computing consistent query answers when queries are posed to virtual XML data integration systems, which are specified following the local-as-view approach. We propose a powerful XML constraint model to define global constraints, which can express keys and functional dependencies, and which also extends the newly introduced conditional functional dependencies to XML. We provide an approach to defining XML views, which supports not only edge-path mappings but also data-value bindings to express the join operator. We give formal definitions of repair and consistent query answers with the XML data integration settings. Given a query on the global system, we present a two-step method to compute consistent query answers. First, the given query is transformed using the global constraints, such that to run the transformed query on the original global system will generate exactly the consistent query answers. Because the global instance is not materialized, the query on the global instance is then rewritten in the form of queries on the underlying data sources by reversing rules in view definitions. We illustrate that the XPath query transformations can be implemented in XQuery. Finally, we implement prototypes of our method and evaluate our algorithms in the experiments. Author Affiliation: (a) School of Computer Science, Fudan University, Shanghai, China (b) Faculty of Information and Communication Technologies, Swinburne University of Technology, Australia Article History: Received 11 December 2009; Revised 6 August 2010; Accepted 9 August 2010
- Published
- 2010
6. Constraint Preserving Transformation from Relational Schema to XML Schema
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Liu, Chengfei, Vincent, Millist W., and Liu, Jixue
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- 2006
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7. Strong functional dependencies and their application to normal forms in XML
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Vincent, Millist W., Liu, Jixue, and Liu, Chengfei
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CD-ROM catalog ,CD-ROM database ,Database ,XML ,Information storage and retrieval systems ,Databases ,XML (Document markup language) - Abstract
In this article, we address the problem of how to extend the definition of functional dependencies (FDs) in incomplete relations to XML documents (called XFDs) using the well-known strong satisfaction approach.We propose a syntactic definition of strong XFD satisfaction in an XML document and then justify it by showing that, similar to the case in relational databases, for the case of simple paths, keys in XML are a special case of XFDs. We also propose a normal form for XML documents based on our definition of XFDs and provide a formal justification for it by proving that it is a necessary and sufficient condition for the elimination of redundancy in an XML document. Categories and Subject Descriptors: H.2.1 [Database Management]: Logical Design--Data models; normal forms; schema and subschema; H.2.3 [Database Management]: Languages--Data description languages (DDL) General Terms: Design, Management, Theory Additional Key Words and Phrases: XML, normalization, functional dependency
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- 2004
8. Context-Based Diversification for Keyword Queries Over XML Data.
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Li, Jianxin, Liu, Chengfei, and Yu, Jeffrey Xu
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ELECTRONIC information resources , *INFORMATION retrieval , *KEYWORDS , *INDEXING , *XML (Extensible Markup Language) - Abstract
While keyword query empowers ordinary users to search vast amount of data, the ambiguity of keyword query makes it difficult to effectively answer keyword queries, especially for short and vague keyword queries. To address this challenging problem, in this paper we propose an approach that automatically diversifies XML keyword search based on its different contexts in the XML data. Given a short and vague keyword query and XML data to be searched, we first derive keyword search candidates of the query by a simple feature selection model. And then, we design an effective XML keyword search diversification model to measure the quality of each candidate. After that, two efficient algorithms are proposed to incrementally compute top-$k$
qualified query candidates as the diversified search intentions. Two selection criteria are targeted: the $k$ selected query candidates are most relevant to the given query while they have to cover maximal number of distinct results. At last, a comprehensive evaluation on real and synthetic data sets demonstrates the effectiveness of our proposed diversification model and the efficiency of our algorithms. [ABSTRACT FROM PUBLISHER]- Published
- 2015
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9. Evaluating Irredundant Maximal Contained Rewritings for XPath Queries on Views.
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Zhou, Rui, Liu, Chengfei, Li, Jianxin, Wang, Junhu, and Yu, Jeffrey Xu
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XPATH (Computer program language) , *REWRITING systems (Computer science) , *QUERY languages (Computer science) , *XML (Extensible Markup Language) , *COMPUTER algorithms - Abstract
We review the problem of finding contained rewritings (CRs) for XPath queries using XPath views. CR is proposed to cater for data integration scenarios, where views are unlikely to be complete due to the limited coverage of data sources, and hence equivalent rewritings are impossible to be found. As a result, we are usually required to find a maximal contained rewriting (MCR) for a query to provide the best possible answers. An MCR is a set of CRs, and may contain redundant CRs. Obviously, evaluating redundant CRs on materialized views is unnecessary. In this paper, we first address how to find the irredundant maximal contained rewriting (IMCR), i.e. all the irredundant CRs. We show that the existing approach ignores a type of situation, and turns out to be not sufficient. As a result, the only safe solution is a brute-force pairwise containment check for all the CRs. We then propose some heuristics to speed up the brute-force comparisons. When a materialized view is given, we propose how to evaluate the IMCR on the materialized view, which, to our knowledge, is the first work on optimizing the evaluation of a set of produced CRs on the materialized view by considering the inherent structural characteristics of the CRs. Our experiments show the effectiveness and efficiency of our algorithms. [ABSTRACT FROM AUTHOR]
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- 2014
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10. XML filtering with XPath expressions containing parent and ancestor axes
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Ning, Bo and Liu, Chengfei
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XML (Extensible Markup Language) , *DATA transmission systems , *COMPUTER users , *COMPUTER systems , *INDEXES , *INFORMATION storage & retrieval systems , *COMPUTER algorithms , *MATHEMATICAL analysis - Abstract
Abstract: More and more XML data is generated and used for data exchange. In this paper, we address the problem of filtering XML documents with large number of XPath expressions, which may contain ‘ancestor’ and ‘parent’ axes. XPath expressions with these axes are more powerful and flexible for users to describe their interests in publish/subscribe systems. First, we analyze the characteristics of the ‘parent’ axis and propose a series of rules to eliminate it in XPath expressions. Then we propose a new index structure called NIndex, which is designed to efficiently store and index large number of XPath expressions. NIndex offers several features which make it especially attractive for the large scale selective dissemination of information, including the ability to handle complex XPath expressions with ‘ancestor’ and ‘parent’ axes, and efficient pruning. Based on NIndex, we design a new filtering algorithm with low complexity for our problem. Our experiment results show that our algorithm performs well across a range of XPath expressions and documents. [Copyright &y& Elsevier]
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- 2012
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11. Discover Dependencies from Data—A Review.
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Liu, Jixue, Li, Jiuyong, Liu, Chengfei, and Chen, Yongfeng
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DATABASES ,PROGRAMMING language semantics ,DATA quality ,FUNCTIONAL dependencies ,DATA mining ,KNOWLEDGE transfer - Abstract
Functional and inclusion dependency discovery is important to knowledge discovery, database semantics analysis, database design, and data quality assessment. Motivated by the importance of dependency discovery, this paper reviews the methods for functional dependency, conditional functional dependency, approximate functional dependency, and inclusion dependency discovery in relational databases and a method for discovering XML functional dependencies. [ABSTRACT FROM PUBLISHER]
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- 2012
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12. XSnippets: Exploring semi-structured data via snippets.
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Naseriparsa, Mehdi, Islam, Md. Saiful, Liu, Chengfei, and Chen, Lu
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XML (Extensible Markup Language) , *DATA structures , *PRUNING - Abstract
Users are usually not familiar with the content and structure of the data when they explore the data source. However, to improve the exploration usability, they need some primary hints about the data source. These hints should represent the overall picture of the data source and include the trending issues that can be extracted from the query log. In this paper, we propose a two-phase interactive exploratory search framework for the clueless users that exploits the snippets for conducting the search on the XML data. In the first phase, we present the primary snippets that are generated from the keywords of the query log to start the exploration. To retrieve the primary snippets, we develop an A* search-based technique on the keyword space of the query log. To improve the performance of computations, we store the primary snippet computations in an index data structure to reuse it for the next steps. In the second phase, we exploit the co-occurring content of the snippets to generate more specific snippets with the user interaction. To expedite the performance, we design two pruning techniques called inter-snippet and intra-snippet pruning to stop unnecessary computations. Finally, we discuss a termination condition that checks the cardinality of the snippets to stop the interactive phase and present the final Top- l snippets to the user. Our experiments on real datasets verify the effectiveness and efficiency of the proposed framework. [ABSTRACT FROM AUTHOR]
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- 2019
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13. A Synthetic, Trend-Based Benchmark for XPath
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Dyreson, Curtis, Jin, Hao, Hutchison, David, Series editor, Kanade, Takeo, Series editor, Kittler, Josef, Series editor, Kleinberg, Jon M., Series editor, Mattern, Friedemann, Series editor, Mitchell, John C., Series editor, Naor, Moni, Series editor, Nierstrasz, Oscar, Series editor, Pandu Rangan, C., Series editor, Steffen, Bernhard, Series editor, Sudan, Madhu, Series editor, Terzopoulos, Demetri, Series editor, Tygar, Doug, Series editor, Vardi, Moshe Y., Series editor, Weikum, Gerhard, Series editor, Chen, Lei, editor, Liu, Chengfei, editor, Liu, Qing, editor, and Deng, Ke, editor
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- 2009
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14. TJDewey – On the Efficient Path Labeling Scheme Holistic Approach
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Bača, Radim, Krátký, Michal, Hutchison, David, Series editor, Kanade, Takeo, Series editor, Kittler, Josef, Series editor, Kleinberg, Jon M., Series editor, Mattern, Friedemann, Series editor, Mitchell, John C., Series editor, Naor, Moni, Series editor, Nierstrasz, Oscar, Series editor, Pandu Rangan, C., Series editor, Steffen, Bernhard, Series editor, Sudan, Madhu, Series editor, Terzopoulos, Demetri, Series editor, Tygar, Doug, Series editor, Vardi, Moshe Y., Series editor, Weikum, Gerhard, Series editor, Chen, Lei, editor, Liu, Chengfei, editor, Liu, Qing, editor, and Deng, Ke, editor
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- 2009
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15. Data Warehouse Based Approach to the Integration of Semi-structured Data
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Ahmad, Houda, Kermanshahani, Shokoh, Simonet, Ana, Simonet, Michel, Hutchison, David, Series editor, Kanade, Takeo, Series editor, Kittler, Josef, Series editor, Kleinberg, Jon M., Series editor, Mattern, Friedemann, Series editor, Mitchell, John C., Series editor, Naor, Moni, Series editor, Nierstrasz, Oscar, Series editor, Pandu Rangan, C., Series editor, Steffen, Bernhard, Series editor, Sudan, Madhu, Series editor, Terzopoulos, Demetri, Series editor, Tygar, Doug, Series editor, Vardi, Moshe Y., Series editor, Weikum, Gerhard, Series editor, Chen, Lei, editor, Liu, Chengfei, editor, Zhang, Xiao, editor, Wang, Shan, editor, Strasunskas, Darijus, editor, Tomassen, Stein L., editor, Rao, Jinghai, editor, Li, Wen-Syan, editor, Candan, K. Selçuk, editor, Chiu, Dickson K. W., editor, Zhuang, Yi, editor, Ellis, Clarence A., editor, and Kim, Kwang-Hoon, editor
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- 2009
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16. Performance analysis and improvement for transformation operators in XML data integration
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Jiashen Tian, Jixue Liu, Millist W. Vincent, Chengfei Liu, Weidong Pan, Tian,Jiashen, Liu, Jixue, Pan, Weidong, Vincent, Millist, Liu, Chengfei, and Pori, Finland 5-9 September
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computer.internet_protocol ,Computer science ,Data transformation (statistics) ,XML validation ,computer.software_genre ,neural, evolutionary and fuzzy computation ,Set (abstract data type) ,XQuery ,Transformation (function) ,080604 [FOR] ,terrestrial ecology ,XML schema ,Data mining ,computer ,XML ,computer.programming_language ,Data integration - Abstract
Data transformation from a source schema to a global schema is an important issue in data integration. For this purpose, a set of transformation operators have been defined to transform both DTDs and the conforming XML documents. In this paper we analyze the performance of individual operators both theoretically and experimentally. The performance of a sequence of operators is also investigated via experiment. Some algorithms and structures are proposed to improve the performance of operators so that linear efficiency can be achieved.The result shows thatmost of the operators can be implemented in linear time to the size of data to be transformed. The performance of sequence of operators is also close to linear. Java and XQuery language are used respectively to implement the operators and their efficiency is compared.
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- 2008
17. A formalism of XML restructuring operations
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Ho-Hyun Park, Chengfei Liu, Jixue Liu, Millist W. Vincent, Liu, Jixue, Park, Ho-Hyun, Vincent, Millist, Liu, Chengfei, and Beijing, China 2007-09-03
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Document Structure Description ,XML Encryption ,Computer science ,computer.internet_protocol ,Efficient XML Interchange ,XML Signature ,Well-formed document ,Document type definition ,computer.software_genre ,Simple API for XML ,XML Schema Editor ,Schema (psychology) ,Streaming XML ,RELAX NG ,XML schema ,Semantic Web ,computer.programming_language ,Information retrieval ,Programming language ,XML validation ,computer.file_format ,XML framework ,XQuery ,XML database ,XML Schema (W3C) ,Document Schema Definition Languages ,Document Definition Markup Language ,ComputingMethodologies_DOCUMENTANDTEXTPROCESSING ,computer ,XML ,XML Catalog - Abstract
We present a set of primitive restructuring operators that, when combined, are sufficiently powerful to convert an XML document under a source schema into an XML document under an arbitrary target schema We initially define the operators at the schema level, and then show how each operator induces a corresponding transformation on any XML document under the schema Finally, we note that our operators can be implemented in a high level language such as XQuery, and thus our approach can be used as the basis for automating the conversion of one XML document to another XML document.
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- 2006
18. Constraint preserving transformation from relational schema to XML schema
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Jixue Liu, Millist W. Vincent, Chengfei Liu, Liu, Chengfei, Vincent, Millist, and Liu, Jixue
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Document Structure Description ,XML Encryption ,Computer Networks and Communications ,Computer science ,Relational database ,computer.internet_protocol ,Efficient XML Interchange ,Semi-structured model ,computer.software_genre ,Information schema ,Relational database management system ,XML Schema Editor ,Data integrity ,Schema (psychology) ,Streaming XML ,RELAX NG ,XML schema ,computer.programming_language ,Database model ,Information retrieval ,Schema migration ,Database schema ,InformationSystems_DATABASEMANAGEMENT ,XML validation ,computer.file_format ,XML Schema (W3C) ,XML database ,Relational calculus ,Hardware and Architecture ,Document Schema Definition Languages ,ComputingMethodologies_DOCUMENTANDTEXTPROCESSING ,Relational model ,computer ,Software ,XML - Abstract
XML has become the standard for publishing and exchanging data on the Web. However, most business data is managed and will remain to be managed by relational database management systems. As such, there is an increasing need to efficiently and accurately publish relational data as XML documents for Internet-based applications. One way to publish relational data is to provide virtual XML documents for relational data via an XML schema which is transformed from the underlying relational database schema such that users can access the relational database through the XML schema. In this paper, we discuss issues in transforming a relational database schema into the corresponding XML schema. We aim to preserve all integrity constraints defined in a relational database schema, to achieve high level of nesting and to avoid introducing data redundancy in the transformed XML schema. In the paper, we first propose a basic transformation algorithm which introduces no data redundancy, then we improve the algorithm by exploring further nesting of the transformed XML schema.
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- 2006
19. Checking multivalued dependencies in XML
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Vincent, Millist, Liu, Jixue, Liu, Chengfei, and Mohania, Mukesh
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multivalued dependency ,Conceptual Modelling ,algorithm ,XML ,performance ,Information Systems - Published
- 2005
20. Redundancy free mappings from relations to XML
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FOURTH INTERNATIONAL CONFERENCE ON WEB-AGE INFORMATION MANAGEMENT, Liu, Chengfei, Liu, Jixue, and Vincent, Millist
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Information Systems Management ,dependancy ,databases ,redundancy ,XML ,Information Systems - Published
- 2004
21. Generalized inclusion dependencies in XML
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Jixue Liu, Chengfei Liu, Solen Dogen, Millist W. Vincent, Michael Schrefl, Liu, Chengfei, Liu, Jixue, Schrefl, Michael, Vincent, Millist, and Dogan,Solen
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Document Structure Description ,Theoretical computer science ,Relational database ,computer.internet_protocol ,Programming language ,Computer science ,XML validation ,computer.software_genre ,Information Systems Management ,XML Schema Editor ,Data integrity ,ComputingMethodologies_DOCUMENTANDTEXTPROCESSING ,XML namespace ,RELAX NG ,XML schema ,computer ,XML ,XML Catalog ,computer.programming_language - Abstract
Integrity constraints play a fundamental role in defining semantics in both conventional databases and in XML documents. In this paper we generalize previous approaches to defining inclusion dependencies in XML. Previous approaches have considered only the case where the paths on the l.h.s. are child attributes of the same node and the paths on the r.h.s. of the dependency are child attributes of the same node, whereas we do not apply this restriction. We then give an axiom system for XINDs and prove that the system is sound and complete. As a corollary, we also show that the implication problem for XINDs is decidable. Finally we consider the relationship between inclusion dependencies in relational databases (INDs) and XINDs in XML documents and we show that for a very general class of mappings from a relational database to a set of XML documents, and IND is satisfied in a relational database if and only if the corresponding XIND is satisfied in the XML documents.
- Published
- 2004
22. A redundancy free 4NF for XML
- Author
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Liu, Chengfei, Liu, Jixue, and Vincent, Millist
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4NF ,relational databases ,data representation ,XML ,dependencies ,semantics - Published
- 2003
23. On transformation to redundancy free XML schema from relational database schema
- Author
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Minyi Guo, Chengfei Liu, Jixue Liu, Liu, Jixue, Liu, Chengfei, and Guo, Minyi
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Document Structure Description ,XML Encryption ,computer.internet_protocol ,Computer science ,Relational database ,Semi-structured model ,Efficient XML Interchange ,computer.software_genre ,Logical schema ,Information schema ,World Wide Web ,Relational database management system ,XML Schema Editor ,Schema (psychology) ,Streaming XML ,RELAX NG ,XML schema ,computer.programming_language ,Database model ,Schema migration ,Database schema ,InformationSystems_DATABASEMANAGEMENT ,XML validation ,computer.file_format ,XML database ,XML Schema (W3C) ,Document Schema Definition Languages ,Star schema ,Document Definition Markup Language ,ComputingMethodologies_DOCUMENTANDTEXTPROCESSING ,computer ,XML - Abstract
While XML is emerging as the universal format for publishing and exchanging data on the Web, most business data is still stored and maintained in relational database management systems. As a result, there is an increasing need to efficiently publish relational data as XML documents for Internet-based applications. One way to publish relational data is to provide virtual XML documents for relational data via an XML schema which is transformed from the underlying relational database schema, then users can access the relational database through the XML schema. In this paper, we discuss issues in transforming a relational database schema into corresponding schema in XML Schema. We aim to achieve high level of nesting while introducing no data redundancy for the transformed XML schema. In the paper, we first propose a basic transformation algorithm which introduces no data redundancy, then we improve the algorithm by exploring further nesting of the transformed XML schema.
- Published
- 2003
24. On transformation to redundancy free XML schema from relational database schema
- Author
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5th Asia-Pacific Web Conference, APWeb 2003, Xian, China, April 23¿25, 2003, Liu, Jixue, Liu, Chengfei, and Guo, Minyi
- Subjects
universal format ,relational database ,transformation ,redundancy free ,data exchange ,XML ,Distributed Computing ,web - Published
- 2003
25. A virtual XML database engine for relational databases
- Author
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Database and XML Technologies, First International XML Database Symposium, XSym 2003, Berlin, Germany, September 8, 2003,Proceedings, Liu, Jixue, Vincent, Millist, Liu, Chengfei, and Guo, Minyi
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relational databases ,translation ,Terrestrial Ecology ,XML ,DBMS ,algorithms ,schema transformation ,Data Format ,database engine - Published
- 2003
26. A virtual XML database engine for relational databases
- Author
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Liu, Jixue, Vincent, Millist, Liu, Chengfei, and Guo, Minyi
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Database Management ,080604 [FOR] ,relational databases ,translation ,XML ,Terrestrial Ecology ,DBMS ,algorithms ,schema transformation ,database engine - Published
- 2003
27. A redundancy free 4NF for XML
- Author
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Database and XML Technologies, First International XML Database Symposium, XSym 2003, Berlin, Germany, September 8, 2003, Liu, Chengfei, Liu, Jixue, and Vincent, Millist
- Subjects
4NF ,relational databases ,data representation ,XML ,dependencies ,semantics ,Data Format - Published
- 2003
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