Thompson, H. S., Beech, D., Maloney, M., & Mendelsohn, N. (2001). XML Schema Part 1: Structures. World Wide Web Consortium, Recommendation. RECxmlschema -1-20010502.  Home/Search   Document Not in Database   Summary   Related Articles   Check

....it has proven useful as a notation for structuring information in general. The syntax of an XML based language is specified using a vocabulary of elements and attributes together with rules for constraining their use. There exists a variety of schema languages, such as DTD [1] XML Schema [2], or DSD2 [3] allowing the syntax to be formalized. An XML document is valid relative to a given schema if all the syntactic requirements specified by the schema are satisfied in the document. The language L(S) of a schema S is the set of XML documents that are valid relative to S. A popular ....

H. S. Thompson, D. Beech, M. Maloney, and N. Mendelsohn, "XML Schema part 1: Structures," May 2001, W3C Recommendation. http://www.w3.org/TR/xmlschema-1/.

....no typing of values is possible. These shortcomings make DTDs unsuited for real schema modeling (in fact, it was always intended as a stop gap method until a more suitable schema language was developed) Developments are well underway at the W3C to replace DTDs with XML Schema definitions [Thompson et al. 2000, Byron and Malhotra, 2000] In practice, XML is being used for a number of rather different purposes: as a serialization syntax for other markup languages. For example, the SMIL multi media markup language [Hoschka, 1998] uses the XML format for its markup syntax. Syntactically, SMIL is ....

....itself nor the DTD specify anything but syntax) only the first usage of XML is in real accordance with the original goal of the language. 1.5.1 XML Schema XML Schemas are a means for defining constraints on valid XML documents. The XML Schema Specification is divided into two parts: in [Thompson et al. 2000] Structures are described, and in [Byron and Malhotra, 2000] Datatypes are described. A human readable explanation on XML Schemas can be found in [Fallside, 2000] XML Schemas have the same purpose as DTDs, but they provide several significant improvements: Figure 1.1: an example XML schema XML ....

Thompson, H. S., Beech, D., Maloney, M., and Mendelsohn, N. (2000). XML Schema Part 1: Structures. Working draft, World Wide Web Consortium (W3C). See http://www.w3.org/TR/xmlschema-1/.

....it has proven useful as a notation for structuring information in general. The syntax of an XML based language is specified using a vocabulary of elements and attributes together with rules for constraining their use. There exists a variety of schema languages, such as DTD [1] XML Schema [2], or DSD2 [3] allowing the syntax to be formalized. An XML document is valid relative to a given schema if all the syntactic requirements specified by the schema are satisfied in the document. The language L(S) of a schema S is the set of XML documents that are valid relative to S. A popular ....

H. S. Thompson, D. Beech, M. Maloney, and N. Mendelsohn, "XML Schema part 1: Structures," May 2001, W3C Recommendation. http://www.w3.org/TR/xmlschema-1/.

.... [5] museums [21] the archival community [11] and those concerned with e commerce and rights management [7] Events, and their role in metadata interoperability, were recognized in [10] Our modeling principles are influenced by work in the W3C and related communities, where both the XML Schema [13, 27] and RDF Schema [15] initiatives are evolving with the goal of formally modeling and representing data (and metadata) on the Web. These efforts and our own build on work in the database community to understand, model, and query semistructured data [9] The remainder of this paper is structured as ....

....(consisting of Time and Place) Event Relations A UML model of these entities and their relationship to each other is shown in the UML [25] model illustrated in Figure 4. This model can be represented declaratively in a schema definition using XML DTDs, RDF Schema [15] or XML Schema Language [13, 27]. We have chosen to provide an XML Schema representation in Figure 5. The remainder of this section describes the entities in this model and our basic approach to an underlying metadata modeling framework. This approach is not final and will continue to be refined through implementation and ....

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H. S. Thompson, D. Beech, M. Maloney, and N. Mendelsohn, "XML Schema Part 1: Structures," World Wide Web Consortium, W3C Working Draft WD-xmlschema-1-2000225, http://www.w3.org/TR/xmlschema-1/, April 7 2000. Appendix A: XML Schema Instantiation of the Scenario The instance document below is a description of the scenario (Event E1) in

....different types as one type using the closure properties, and (c) the ability to represent recursive relationships. 1 Introduction With the growing popularity of XML (eXtensible Markup Language) 5] defined by W3C, XML schemas expressed by schema languages (e.g. DTD [5] XML Schema [14], RELAX [9] are being widely used to describe data. Even though XML is largely used for transferring data at present, we envision that in the not so distant future, XML schemas will be used as the external schema for a large portion of the data. This makes the study of modeling capabilities of ....

....language theory. The important building blocks of any XML schema language such This author is partially supported by NSF grants 0086116, 0085773, 9817773. x We differentiate two terms XML schema(s) and XML Schema. The former refers to a general term for a schema for XML, while the latter [14] refers to one kind of XML schema language proposed by W3C. Dept (1,1) tEmployee Fig. 1. Cardinality representation in ER model. as element subelement relationships are well captured in XGrammar in a coherent and precise manner. We describe three features of XGrammar in detail and ....

H. S. Thompson, D. Beech, M. Maloney, and N. Mendelsohn (Eds). "XML Schema Part 1: Structures". W3C Recommendation, May 2001. http:/ /www.w3.org/TR/xmlschema-1/.

....in relational databases. Therefore, we expect the needs to convert such relational data into XML documents will grow substantially as well. In this paper, we study the problems in this conversion. Especially, we are interested in finding XML schema (e.g. DTD [3] RELAX NG [5] XML Schema [22]) that best describes the existing relational schema. Having an XML schema that precisely describes the semantics and structures of the original relational data is important to further maintain the converted XML documents in future. At present, there exist several tools that enable the ....

....by human experts explicitly. We first present a straightforward relational to XML trans1 We di#erentiate two terms XML schema(s) and XMLSchema. The former refers to a general term for schema in XML model while the latter refers to one particular kind of XML schema language proposed by W3C [22]. http: www 4.ibm.com software data db2 extenders xmlext http: www.rpbourret.com xmldbms index.htm lation algorithm, called Flat Translation (FT) Since FT maps the flat relational model to the flat XML model in a one to one manner, it does not utilize the regular expression operators ....

H. S. Thompson, D. Beech, M. Maloney, and N. Mendelsohn (Eds). "XML Schema Part 1: Structures". W3C Recommendation, May 2001. http://www.w3.org/TR/xmlschema-1/.

.... We shall use the branching factor b (i.e. number of children) of node v to di#erentiate their operation costs as follows: cost(v) b(v) number of children of v base of v where base of v is either the number of maximum possible children of v that can be obtained from the XML schema [TBM01, BM01], or the average number of children of v obtained by mining the XML documents a priori. For instance, consider the following XML DTD describing a dept element: Note that the dept element has either div sub element or a pair of title and manager sub elements. Further, the div element has a ....

....relational databases. Therefore, we expect the needs to convert such relational data into XML documents will grow substantially as well. In this Chapter, we study the problems in this conversion. Especially, we are interested in finding XML schema (e.g. DTD [BPS00] RELAX NG [CM01] XML Schema [TBM01]) that best describes the existing relational schema. Having an XML schema that precisely describes the semantics and structures of the original relational data is important to further maintain the converted XML documents in future. At present, there exist several tools that enable the ....

[Article contains additional citation context not shown here]

H. S. Thompson, D. Beech, M. Maloney, and N. Mendelsohn (Eds). "XML Schema Part 1: Structures". W3C Recommendation, May 2001. http://www.w3.org/TR/xmlschema-1/.

....laid by the predefined property RDF:Type, which can be used in statements like any other property, except that neither the subject nor the object can be a literal. The type system for literals is left up to the encoding, in the case of XML this means the XML Datatypes[1] section of the XML Schema [9]definition. Relations between types is further elaborated in RDF Schemas. RDF also allows statements to be made about statements, for instance to represent that the statement above about CPU utilization came from the program top. To do this, RDF defines a mechanism for transforming a statement ....

H. Thompson, et. al., eds.,"XML Schema Part 1: Structures", W3C Working Draft 25 February 2000. http://www.w3.org/TR/xmlschema-1

....different types as one type using the closure properties, and (c) the ability to represent recursive relationships. 1 Introduction With the growing popularity of XML (eXtensible Markup Language) 5] defined by W3C, XML schemas 1 expressed by schema languages (e.g. DTD [5] XMLSchema [14], RELAX [9] are being widely used to describe data. Even though XML is largely used for transferring data at present, we envision that in the not so distant future, XML schemas will be used as the external schema for a large portion of the data. This makes the study of modeling capabilities of ....

....language theory. The important building blocks of any XML schema language such This author is partially supported by NSF grants 0086116, 0085773, 9817773. 1 We differentiate two terms XML schema(s) and XML Schema. The former refers to a general term for a schema for XML, while the latter [14] refers to one kind of XML schema language proposed by W3C. has Dept Employee (1, 1,1) Fig. 1. Cardinality representation in ER model. as element subelement relationships are well captured in XGrammar in a coherent and precise manner. We describe three features of XGrammar in detail and ....

H. S. Thompson, D. Beech, M. Maloney, and N. Mendelsohn (Eds). "XML Schema Part 1: Structures". W3C Recommendation, May 2001. http://www.w3.org/TR/xmlschema-1/.

....at conf element. Note that when a root element is not specified in a DTD (i.e. no DOCTYPE root clause is given) a valid XML document can be rooted at any level of the DTD hierarchy as long as their sub elements and attributes are valid. 5 XML Schema: XML Schema 1 (Fallside (Eds) 2001; Thompson et al. 2001; Biron and Malhotra (Eds) 2001) is an ongoing effort of W3C as a next generation XML schema language. XML Schema aims to be more expressive than DTD and more usable by a wider variety of applications. It has many novel mechanisms such as inheritance for attributes and elements, user defined ....

Thompson, H. S., Beech, D., Maloney, M., Mendelsohn (Eds), N., May 2001. "XML Schema Part 1: Structures". W3C Recommendation, http://www.w3.org/TR/xmlschema-1/.

....(b) instance tree Table 2: A grammar and instance tree representation corresponding to XML schema and document in Table 1. ffl The database and web community use terms such as schema and XML document. Schema is considered to be an abstract definition of the set of conforming XML documents [TBME00] Example is shown in Table 1. ffl The formal language community (the oldest community to have studied trees as defined in XML) uses terms such as grammars, instance tree, automata, and language. A grammar defines an abstract set of trees (i.e. instance trees) language denotes the set of trees ....

....on the following observations and Lemmas 1 and 2. ffl There is an increased interest to separate the two parts in a production rule of a tree regular grammar in schema proposals. Hedge rules in RELAX [Mur00b] regular expression types in XDuce [HVP00] and complex type definitions in XML Schema [TBME00] are examples. ffl After we separate the two subparts, we should ensure that the content of an element describes a regular string language and not a context free language. RELAX ensures this by disallowing recursion in hedgeRules, and XDuce allows only right linear grammars. ffl Orthogonal ....

[Article contains additional citation context not shown here]

H. S. Thompson, D. Beech, M. Maloney, and N. Mendelsohn (Eds.). "XML Schema Part 1: Structures", Sep. 2000. http://www.w3.org/TR/xmlschema-1/.

....resource. At this point we have experimented with the ABC model for mapping between a number of metadata schemas including Dublin Core, ID3 tags embedded in MP3, MPEG 7 descriptions in DDL, and the CIDOC CRM model. We have demonstrated that it is possible to do simple mappings using XML schema [6, 38] and XSLT [14] The limitations of these tools has constrained the expressiveness of these mappings and in Harmony we are beginning to experiment with more powerful tools such as a metadata term ontology and the use of a general mapping rule language. Conclusion This paper has proposed radical ....

H. S. Thompson, D. Beech, M. Maloney, and N. Mendelsohn, "XML Schema Part 1: Structures," World Wide Web Consortium, W3C Working Draft WD-xmlschema-1-2000225, http://www.w3.org/TR/xmlschema-1/, April 7 2000.

.... of XML make it a far more powerful tool for data representation and access than SGML, including means for complex linkage within and between documents, easy data transformations using the XML Transformation Language (XSLT) Clark, 1999) constraint and validation of markup using XML Schemas (Thompson, et al. 2000; Biron Malhotra, 2000) and display, manipulation, and search of data via the World Wide Web. This paper provides an overview of the most important XML mechanisms and suggests how they may impact the design of language processing tools. The focus here is on the use of XML for the creation and ....

.... Romary (2000) show how XSLT can implement inheritance mechanism for lexical information. xmnls:xsl= http: www.w3. org 1999 XSL Transform xsl:text xsl:text xsl:text xsl:text Figure 2 : XSLT document to create HTML output 3 XML Schemas The XML Schema definition language (Thompson, et al. 2000; Biron Malhotra, 2000) enables document creators to constrain and document the meaning, usage and relationships of the constituent parts of XML documents: datatypes, elements and their content, and attributes and their values. Schemas can also be used to provide default values for attributes ....

Thompson, H., Beech, D., Maloney, M. Mendelsohn, N., 2000. XML Schema Part 1: Structures. W3C Working Draft, 25 February 2000.

....necessary to be able to refer to this information in stylesheets, for example to create a menu of allowable attributes. We have done this by adding new commands to the stylesheet language which provide iteration over element and attribute definitions in the DTD. With the development of XML Schemas [Thompson, 1999] to replace DTDs, this may become possible in XSLT in the future. Because we want actions on the user display to have effects on the underlying corpus (i.e. we want to support editing) we need to keep back pointers from the display objects to the parts of the corpus which they refer to. Since ....

Thompson. H.S., Beech, D., Maloney, M. & Mendelsohn, N. (1999). XML Schema Part 1: Structures. World Wide Web Consortium, Working Draft December 1999. See http://www.w3.org/TR/xmlschema-1/

....this information in stylesheets, for example to create a menu of allowable attributes. We have done this by adding new commands to the stylesheet language which provide iterators over element and attribute de nitions in the DTD. An alternative approach, currently being developed by the XML Schema [Thompson et al. 2000] working group of the World Wide Web Consortium (W3C) and others, is to say that DTDs are not a suciently expressive data modelling language, and to seek to de ne an extended schema language for XML. Such a schema language can be coded in XML itself and hence the standard XSLT queries and ....

Thompson, H. S., Beech, D., Maloney, M., and Mendelsohn, N. (2000). XML Schema part 1: Structures. World Wide Web 27 Consortium. www.w3.org/TR/xmlschema-1.

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Thompson, H. S., Beech, D., Maloney, M., & Mendelsohn, N. (2001). XML Schema Part 1: Structures. World Wide Web Consortium, Recommendation. RECxmlschema -1-20010502.

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Beech D, Lawrence S, Moloney M, Mendelsohn N, Thompson, HS (2001) XML Schema Part 1: Structures. W3C Recommendation 02 May, World Wide Web Consortium.

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Beech D, Lawrence S, Moloney M, Mendelsohn N, Thompson, HS (2001) XML Schema Part 1: Structures. W3C Recommendation 02 May, World Wide Web Consortium.

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H. Thompson, D. Beech, M. Maloney, and N. Mendelsohn, "XML schema part 1: Structures," W3C Recommentation, May 2001. http://www.w3.org/TR/xmlschema-1/.

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H. S. Thompson, D. Beech, M. Maloney, and N. Mendelsohn, "XML Schema Part 1: Structures." W3C Recommendation 2 May 2001.

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H. S. Thompson, D. Beech, M. Maloney, and N. Mendelsohn, "XML Schema part 1: Structures," May 2001, W3C Recommendation. http://www.w3.org/TR/xmlschema-1/.

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Thompson, H., Beech, D., Maloney, M. and N. Mendelsohn, "XML Schema Part 1: Structures", W3C REC-xmlschema-1, May 2001, <http://www.w3.org/TR/xmlschema-1/>.

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H.S. Thompson, D. Beech, M. Maloney, and N. Mendelsohn. "XML schema part 1: Structures", W3C Recommendation, October, 2000.

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H. S. Thompson, D. Beech, M. Maloney, and N. Mendelsohn, "XML Schema part 1: Structures," May 2001, W3C Recommendation. http://www.w3.org/TR/xmlschema-1/.

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H. S. Thompson, et al., "XML Schema Part 1: Structures," W3C, working-in-progress, current as of Apr. 2000; available online at http://www.w3.org/TR/2000/WDxmlschema -1-20000407/.

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