Abstract: XML is fast emerging as the dominant standard for representing data in the World Wide Web. Sophisticated query engines that allow users to effectively tap the data stored in XML documents will be crucial to exploiting the full power of XML. While there has been a great deal of activity recently proposing new semistructured data models and query languages for this purpose, this paper explores the more conservative approach of using traditional relational database engines for processing XML documents conforming to Document Type Descriptors (DTDs). To this end, we have developed algorithms and implemented a prototype system that converts XML documents to relational tuples, translates semi-structured queries over XML documents to SQL queries over tables, and converts the results to XML. We have qualitatively evaluated this approach using several real DTDs drawn from diverse domains. It turns out that the relational approach can handle most (but not all) of the semantics of semi-structured queries over XML data, but is likely to be effective only in some cases. We identify the causes for these limitations and propose certain extensions to the relational model that would make it more appropriate for processing queries over XML documents.

Abstract: Research on semistructured data over the last several years has focused on data models, query languages, and systems where the database is modeled as some form of labeled, directed graph. The recent emergence of eXtensible Markup Language (XML) as a new standard for data representation and exchange on the World-Wide Web has drawn significant attention. Researchers have casually observed a striking similarity between semistructured data models and XML. While similarities do abound, some key differences dictate changes to any existing data model, query language, or DBMS for semistructured data in order to fully support XML. This paper describes our experiences migrating the Lore database management system for semistructured data to work with XML. We present our modified data model, whose definition was a subtly challenging task given that XML itself is just a textual language. Based on this model, we describe changes to Lorel, Lore's query language. We also briefly discuss changes to Lore's dynamic structural summaries (DataGuides) and the relationship of DataGuides to XML's Document Type Definitions (DTDs).

Abstract: XML is emerging as one of the dominant data formats for data processing on the Internet. To query XML data, query languages like XQL, Lorel, XML-QL, or XML-GL have been proposed. In this paper, we study how XML data can be stored and queried using a standard relational database system. For this purpose, we present alternative mapping schemes to store XML data in a relational database and discuss how XML-QL queries can be translated into SQL queries for every mapping scheme. We present the results of comprehen- sive performance experiments that analyze the tradeoffs of the alternative mapping schemes in terms of database size, query performance and update performance. % The results show clearly that a variant of a binary mapping scheme % shows the overall best performance While our discussion is focussed on XML and XML-QL, the results of this paper are relevant for most semi-struct- ured data models and most query languages for semi-structured data.

Abstract: The MIX mediator system, MIXm, is developed as part of the MIX Project at the San Diego Supercomputer Center, and the University of California, San Diego.1 MIXm uses XML as the common model for data exchange. Mediator views are expressed in XMAS (XML Matching And Structuring Language), a declarative XML query language. To facilitate user-friendly query formulation and for optimization purposes, MIXm employs XML DTDs as a structural description (in effect, a “schema”) of the exchanged data. The novel features of the system include: Data exchange and integration solely relies on XML, i.e., instance and schema information is represented by XML documents and XML DTDs, respectively. XML queries are denoted in XMAS, which builds upon ideas of languages like XML-QL, MSL, Yat, and UnQL. Additionally, XMAS features powerful grouping and order constructs for generating new integrated XML “objects” from existing ones.The graphical user interface BBQ (Blended Browsing and Querying) is driven by the mediator view DTD and integrates browsing and querying of XML data. Complex queries can be constructed in an intuitive way, resembling QBE. Due to the nested nature of XML data and DTDs, BBQ provides graphical means to specify the nesting and grouping of query results.Query evaluation can be demand-driven, i.e., by the user's navigation into the mediated view.

Abstract: Systems, methods and computer program products are provided for utilizing XML-based tools to tailor HTML-based Web page content for display within various client devices. Content portions of a requested Web page are converted to an XML format and then modified using an XML content-tailoring tool. Other content portions of the Web page are masked so as to be “hidden” and are, thus, not converted to XML format. The masked portions of the Web page are then unmasked, combined with the modified content portions, and transmitted to a client device for display therewithin.

Abstract: We present two complementary approaches to writing XML document-processing applications in a functional language.In the first approach, the generic tree structure of XML documents is used as the basis for the design of a library of combinators for generic processing: selection, generation, and transformation of XML trees.The second approach is to use a type-translation framework for treating XML document type definitions (DTDs) as declarations of algebraic data types, and a derivation of the corresponding functions for reading and writing documents as typed values in Haskell.

Abstract: In a computer system executing a repository program and having a memory, a method is disclosed for identifying UML objects in the repository with objects in an XML file. The method includes the steps of parsing the XML file into XML objects and building an object tree. Next, the object tree is traversed a first time, and for each XML object found that has a name, corresponding UML objects are identified. After this, the object tree is traversed a second time, and for each XML object found that does not have a name, corresponding UML objects are then identified through Compositions and References. The method for traversing said object tree a first time includes the steps of identifying a UML object type for each XML object, and when the XML object name matches the UML object name at the current level, a UML and XML object IDs are saved in a ‘Conversion’ object in the memory.

Abstract: In a computer system executing a repository program and having a memory, a method is disclosed for versioning a UML model in the repository in accordance with an updated XML representation of the UML model. The method includes the steps of identifying differences between UML objects in the UML model and XML objects in the XML file. Where there is a difference between one of the UML objects and one of the XML objects, it is reserved as a ghost object. The ghost object is updated to match each corresponding one of the XML objects. Objects whose target references have been changed are reserved and updated. Finally, the UML objects are updated in the repository that refer to ghost objects updated in the preceding step. The method includes making changes to the ghost object Attributes, References and owned elements to match Attributes, References and owned elements, respectively, found in the XML object.

Abstract: From the Publisher: "Now revised and expanded to cover the latest XML technologies and applications, this all-in-one tutorial and reference shows you step by step how to put the power of XML to work in your Web pages. From document type definitions and style sheets to XPointers, schemas, the Wireless Markup Language, XHTML and other advanced tools and applications, XML expert Elliotte Rusty Harold gives you all the know-how and examples you need to integrate XML with HTML, solve real-world development challenges, and create data-driven content."--BOOK JACKET.

Abstract: XML (eXtensible Markup Language) is becoming the most relevant standardization effort in the area of document representation through markup languages Through XML, it is possible to define complex documents, containing information at different degrees of sensitivity Moreover, the processes of document exchange and acquisition, which can be very frequent in Web-based information systems, are simplified and standardized In this scenario, there is a strong need for policies to control and regulate the access and dissemination of XML documents In the paper, we discuss main protection requirements posed by XML documents and we present a set of authorization and dissemination policies that enable both a controlled access to XML documents in a given source and the exchange of XML documents across different sources

Abstract: Current research in software reengineering offers a great amount of tools specialized on certain reengineering tasks. The definition of a powerful common interchange format is a key issue to provide interoperability between these tools. This paper discusses aspects of data interchange formats for exchanging reengineering related data. It proposes a graph-based format to exchange both application specific concepts and data by XML documents.

Abstract: From the Publisher: XML and Java : Developing Web Applications is a tutorial that will teach Web developers, programmers, and system engineers how to create robust XML business applications for the Internet using the Java technology. Readers should have a basic understanding of XML as well as experience in writing simple Java programs.

Abstract: XML threatens to expand beyond its document markup origins to become the basis for data interchange on the Internet. One highly anticipated application of XML is the interchange of electronic data (EDI). Unlike existing Web documents, electronic data is primarily intended for computer, not human, consumption. For example, businesses could publish data about their products and services, and potential customers could compare and process this information automatically; business partners could exchange internal operational data between their information systems on secure channels; search robots could integrate automatically information from related sources that publish their data in XML format, like stock quotes from financial sites, sports scores from news sites. New opportunities will arise for third parties to add value by integrating, transforming, cleaning, and aggregating XML data. Once it becomes pervasive, it’s not hard to imagine that many information sources will structure their external view as a repository of XML data, no matter what their internal storage mechanisms. Data exchange between applications will then be in XML format. What is then the role of a query language in this world? One could see it as a local adjunct to a browsing capability, providing a more expressive “find” command over one or more retrieved documents. Or it might serve as a souped-up version of XPointer, allowing richer forms of logical reference to portions of documents. Neither of these modes of use is very “databasey”. From the database viewpoint, the enticing role of an XML query language is as a tool for structural and content-based query that allows an application to extract precisely the information it needs from one or several XML data sources. One salient question is why not adapt SQL or OQL to query XML. The answer is that XML data is fundamentally different from relational and object-oriented data, and therefore, neither SQL nor OQL is appropriate for XML. The key distinction between data in XML and data in traditional models is that XML is not rigidly structured. In the relational and object-oriented models, every data instance has a schema, which is separate from and independent of the data. In XML, the schema exists with the data. Thus, XML data is self-describing and can naturally model irregularities that cannot be modeled by relational or object-oriented data. For example, data items may have missing elements or multiple occurrences of the same element; elements may have atomic values in some data items and structured values in others; and collections of elements can have heterogeneous structure. Even XML data that has an associated DTD is self-describing (the data can still be parsed, even if

Abstract: In this paper we present the World-Wide WebWrapper Factory (W4F), a Java toolkit to generate wrappers for Web data sources. Some key features of W4F are an expressive language to extract information from HTML pages in a structured way, a mapping to export it as XML documents and some visual tools to assist the user during wrapper creation. Moreover, the entire description of wrappers is fully declarative. As an illustration, we demonstrate how to use W4F to create XML gateways, that serve transparently and onthe-fly HTML pages as XML documents with their DTDs. Comments Postprint version. Copyright ACM, 1999. This is the author’s version of the work. It is posted here by permission of ACM for your personal use. Not for redistribution. The definitive version was published in WebDB '99. This conference paper is available at ScholarlyCommons: http://repository.upenn.edu/db_research/24

Abstract: Unified Modeling Language (UML) has been widely accepted as an object-oriented analysis/design methodology in the software engineering community, and is in the process of revised standardization at OMG (Object Management Group). One of the current major enhancements is SMIF (Stream-based Model interchange Format) specification, which aims to interchange UML models in a standard based way. It is expected to be based on XML (eXtensible Markup language) standard and used in various development tools such as CASE tools, automatic documentation tools and repositories. This paper addresses a standard-based UML model interchange and presents our effort to make UML interoperable. We developed a XML-based exchange format called UXF (UML eXchange Format) and a distributed model management system for UML. The system leverages the team development reuse of design models and tool interoperability by interchanging the model information with XML through the Document Object Model (DOM) interface that is implemented on top of CORBA (Common Object Request Broker Architecture). DOM provides a platform and programming language neutral interface to manipulate the content, structure and style of documents. Our work shows a practical application of some key standards in terms of the software model interchange. It provides multiple levels of interoperability for UML, thereby UML models can be highly interoperable.

Abstract: The Web is explored by many users, but only a few of them have experience in using query languages. Thus, one of the greatest challenges, provided by XML, is to create a query language simple enough for the naive user. In this paper, we present EquiX|a powerful and easy to use query language for XML. The main goal in designing EquiX is to strike the right balance between expressive power and simplicity. EquiX has a form-based GUI that is constructed automatically from the DTDs of XML documents. Query forms are built from well known HTML primitives. The result of a query in EquiX is a collection of XML documents, and it is automatically generated from the query without explicit speci cation of the format of the result. Knowledge of XML syntax is not required in order to use EquiX. Yet, EquiX is able to express rather complicated queries, containing quanti cation, negation and aggregation. We present the data model in Section 2. In Sections 3, and 4 we introduce the query language syntax, and semantics. Automatic generation of query results is discussed in Section 6. In Section 7, we review related work and conclude.

Abstract: A method and apparatus are disclosed for streaming XML content in a manner that allows the receiver to decode the XML data that is actually received, even if an entire XML document is not received. Each XML document is decomposed and encoded as a collection of sub-trees. Each sub-tree from the larger XML document tree can be parsed and validated by the XML receiver as if it is an independent tree. Each streamed XML document utilizes a structure node that serves as a sub-tree wrapper function around each independent sub-tree. The structure node indicates the relationship of the sub-tree to other sub-trees, thereby allowing the XML receiver to reconstruct the full tree.

Abstract: This memo presents a technique for using XML (Extensible Markup Language) as a source format for documents in the Internet-Drafts (I-Ds) and Request for Comments (RFC) series.

Abstract: From the Publisher: Building XML Applications is your guide into this robust and flexible markup language which is revolutionizing the way information is presented, stored, and processed. With XML and Java, you can create the next generation of distributed Internet/Network applications. This book clearly explains XML and also walks you through the creation of real applications.

Abstract: Many companies have a wealth of information in their databases and applications, and want to leverage these assets. They are beginning to see that XML could help them do this by providing a standard data format for cross-platform information exchange. XML thus offers a powerful new way to integrate new and existing applications within companies. Today much of that linking must be done using enterprise application integration software, which is often complex and quite costly. Developers may have to translate legacy APIs to new component APIs or change flow data and workflow processes are structured to permit data exchange between incompatible applications. Analysts and some early adopters say XML will help simplify this complex, labor-intensive process because it lets developers precisely identify pieces of data on the basis of content.

Abstract: A catalog clearinghouse is defined as an electronic commerce entity that provides a common web-based storefront to a group of merchants. This paper considers the implementation of a specific kind of clearinghouse: one that hosts catalogs for a large number of similar merchants (e.g., thousands of restaurant menus). A standard architecture is described. followed by a novel architecture that uses the emerging Extensible Markup Language (XML) and Extensible Stylesheet Language (XSL) standards for data storage, search and graphical presentation. For large clearinghouses, the new architecture realizes significant benefits in terms of presentation flexibility, powerful search capabilities and increased performance. XML and XSL are used at the client side for flexible presentations with low maintenance costs, while XML and traditional RDBMS techniques are combined at the server for searching and business logic. Detailed examples of XML document type definitions and XML structured data are given, along with details on the recursive transformation of XML into HTML, using rule-based XSL style sheets.

Abstract: The Mediation of Information using XML (MIX) project is a joint effort between the the San Diego Supercomputer Center (SDSC) and the Database Lab at the University of California, San Diego where we are investigating the use of XML as the medium for information modeling and information interchange among heterogeneous information sources. Relational databases represent an important type of information source. We discuss issues in providing XML document views of relational schemas. We refer to these as, XViews. We also discuss related work from a project funded by DARPA and the US Patent and Trademark Office where we investigated issues in mapping SGML document type definitions to relational schemas. The work described here reflects initial results from the above mentioned projects.

Abstract: Extensible Markup Language (XML) is the universal format for data on the Web. It allows developers to easily describe and deliver rich, structured data from any application in a standard, consistent way. "XML in Action" is a valuable, insightful guide for a growing army of HTML/Web authors eager to develop richer and more efficient Web applications and Web pages using XML as featured in Microsoft Internet Explorer 5 (supported by Netscape as well). "XML in Action" is a valuable blueprint for impactful, hard-working Web sites.

Abstract: Active networks are an example of a wide area distributed system. The objects in this system require platform independent machine-readable, flexible behaviour specifications. Current mechanisms in CORBA, DCOM and similar technologies are not adequate. We demonstrate for the first time how specifications with the required properties can be written in XML, the new language of the WWW.

Abstract: From the Publisher: XML, the Extensible Markup Language, is the next-generation markup language for the Web. It provides a more structured and more powerful medium than HTML, allowing us to define new document types and stylesheets as needed. Although the generic tags of HTML are sufficient for everyday text, XML gives us a way to add rich, well-defined markup to electronic documents. The XML Pocket Reference, Second Edition, is both a handy introduction to XML terminology and syntax, and a quick reference to XML instructions, attributes, entities, and datatypes. Although XML itself is complex, its basic concepts are simple. This small book serves both as a perfect tutorial for learning the basics of XML, and as a reference to the XML specification. This second edition includes information on XSLT (Extensible Stylesheet Language Transformations) and XPath.

Abstract: XML data are expected to be widely used in Web information systems and EC/EDI applications. Such applications usually use a large number of XML data. First, we must allow users to retrieve only necessary portions of XML data by specifying search conditions to flexibly describe such applications. Second, we must allow users to combine XML data from different sources. To this end, we will provide a query language for XML data tentatively called XQL. We have designed XQL, keeping in mind its continuity with database standards such as SQL and OQL although we don't stick to its strict conformity. In this paper, we describe the requirements for a query language for XML data and explain the functionality of XQL including XML version of database operators such as select, joint, sort, grouping, union, and view definition. We make brief comments on the implementation and semantics.

Abstract: We regard the delivery of radiological information as an interactive multimedia report. We use a multimedia report model based on Extensible Markup Language (XML), rather than a traditional workstation model. Others have suggested a similar document-based approach. This display presentation includes imagerelated and text-based information and may contain interactive components (eg, window, level and zoom). Using XML as a foundation for this multimedia presentation, we achieve flexibility and platform independence at a lower cost. XML allows for the separation of content and form. Content information, defined as elements (eg, images, radiologic reports, and demographic information), is treated as independent information objects. The behavior of the elements can be changed for different users and tasks. In addition, by separating format detail from content, the appearance of the elements within the report can be modified. XML does not replace existing standards (ie, Digital Imaging and Communications in Medicine [DICOM], Transmission Control Protocol/Internet Protocol [TCP/IP]). Instead, it provides a powerful framework that is used in combination with existing standards to allow system designers to modify display characteristics based on user need. We describe our application of XML to the clinical display of radiologic information.

Abstract: XML can play several roles in a distributed object system. In particular, data can be serialized in XML-based formats. XML-encoded data can be more self-describing than data encoded in many more traditional ways, which facilitates the kind of decentralized protocol evolution seen in Internet-scale development: XML's explicit "tagging and bagging" helps keep extensions straight. However, today's common distributed object systems have type systems that are not flexible enough to describe such data. We suggest a way to make more flexible data types; this improves distributed object systems in general, and is critical to realizing XML's full potential. This approach has: (1) typing judgements based on type structure instead of type identity, (2) extensible record types with optional fields, (3) coarse record types, for which extension is compatible with subtyping, and (4) non-ignorable fields in record values.