Subsumption for XML types

XML data is often used (validated, stored, queried, etc) with respect to different types. Understanding the relationship between these types can provide important information for manipulating this data. We propose a notion of subsumption for XML to capture such relationships. Subsumption relies on a syntactic mapping between types, and can be used for facilitating validation and query processing. We study the properties of subsumption, in particular the notion of the greatest lower bound of two schemas, and show how this can be used as a guide for selecting a storage structure. While less powerful than inclusion, subsumption generalizes several other mechanisms for reusing types, notably extension and refinement from XML Schema, and subtyping.

[1]  Yannis Papakonstantinou,et al.  DTD inference for views of XML data , 2000, PODS.

[2]  John C. Mitchell,et al.  Foundations for programming languages , 1996, Foundation of computing series.

[3]  Benjamin C. Pierce,et al.  Xduce: an xml processing language , 1999 .

[4]  Benjamin C. Pierce,et al.  Regular expression types for XML , 2000, TOPL.

[5]  Jennifer Widom,et al.  The Lorel query language for semistructured data , 1997, International Journal on Digital Libraries.

[6]  Dan Suciu,et al.  Type inference for queries on semistructured data , 1999, PODS '99.

[7]  Roy Goldman,et al.  DataGuides: Enabling Query Formulation and Optimization in Semistructured Databases , 1997, VLDB.

[8]  Luca Cardelli,et al.  A Semantics of Multiple Inheritance , 1984, Inf. Comput..

[9]  Alin Deutsch,et al.  Storing semistructured data with STORED , 1999, SIGMOD '99.

[10]  Mary Fernandez.  XML Query Languages: Experiences and Exemplars , 2001 .

[11]  Alin Deutsch,et al.  A Query Language for XML , 1999, Comput. Networks.

[12]  Sophie Cluet,et al.  Your mediators need data conversion! , 1998, SIGMOD '98.

[13]  Catriel Beeri,et al.  Schemas for Integration and Translation of Structured and Semi-structured Data , 1999, ICDT.

[14]  Vassilis Christophides,et al.  On wrapping query languages and efficient XML integration , 2000, SIGMOD 2000.

[15]  Dan Suciu,et al.  Optimizing regular path expressions using graph schemas , 1998, Proceedings 14th International Conference on Data Engineering.

[16]  C. M. Sperberg-McQueen,et al.  Extensible markup language , 1997 .

[17]  Dan Suciu,et al.  Adding Structure to Unstructured Data , 1997, ICDT.

[18]  Nils Klarlund,et al.  DSD: A schema language for XML , 2000, FMSP '00.

[19]  Raghu Ramakrishnan,et al.  Database Management Systems , 1976 .

[20]  François Pottier,et al.  Type Inference in the Presence of Subtyping: from Theory to Practice , 1998 .

[21]  Jérôme Siméon,et al.  YATL: a Functional and Declarative Language for XML , 2000 .

[22]  David J. DeWitt,et al.  Relational Databases for Querying XML Documents: Limitations and Opportunities , 1999, VLDB.

[23]  Guido Moerkotte,et al.  Querying documents in object databases , 1997, International Journal on Digital Libraries.

[24]  Diego Calvanese,et al.  Representing and Reasoning on XML Documents: A Description Logic Approach , 1999, J. Log. Comput..

[25]  François Pottier.  Synthese de types en presence de sous-typage : de la theorie a la pratique , 1998 .

[26]  Benjamin C. Pierce,et al.  XDuce: A Typed XML Processing Language (Preliminary Report) , 2000, WebDB.

[27]  Kyuseok Shim,et al.  XTRACT: a system for extracting document type descriptors from XML documents , 2000, SIGMOD '00.

[28]  Sophie Cluet,et al.  Using YAT to Build a Web Server , 1998, WebDB.

[29]  Vassilis Christophides,et al.  On wrapping query languages and efficient XML integration , 2000, SIGMOD '00.

[30]  Dan Suciu,et al.  Typechecking for XML transformers , 2000, J. Comput. Syst. Sci..

[31]  C. M. Sperberg-McQueen,et al.  Extensible Markup Language (XML) , 1997, World Wide Web J..

[32]  John Cowan,et al.  Document Definition Markup Language (DDML) Specification, Version 1.0 , 1999 .