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W3C XML Query Language Working Group

W3C XML Query Language Working Group. Mark Needleman Data Research Associates ZIG Current Awareness Session July 13, 2000. Other DRA Interest. XML in General HTML CSS Accessibility Initiative Metadata - RDF Privacy Electronic Commerce URI’s. QL Working Group Charter.

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W3C XML Query Language Working Group

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  1. W3C XML Query Language Working Group Mark Needleman Data Research Associates ZIG Current Awareness Session July 13, 2000

  2. Other DRA Interest • XML in General • HTML • CSS • Accessibility Initiative • Metadata - RDF • Privacy • Electronic Commerce • URI’s

  3. QL Working Group Charter • Formal Data Model based on XML Infoset • Formal Algebra • One or More Concrete Canonical Syntaxes based on Data Model and Algebra - One Syntax must be expressed in XML - One Syntax must be “Human Friendly”

  4. QL Workshop 98 • W3C sponsored event - Boston Dec 2-3 • 98 participants - 66 position papers • W3C members, database vendors, invited experts • See: • http://www.w3.org/Tands/QL/QL98

  5. W3C QL WG History and Status • Proposed July 1999 as part of XML Phase 3 Activity • September 99 - Call for Participants and group chartered • 1st Face to Face meeting - Sept 15-16 • 2nd Face to Face December 2-3 • 3rd Face to Face February 7-8, 2000

  6. Status (2) • 4th F2F April 11-12 2000 • 5th F2F June 5-6, 2000 • 3 more F2F meetings scheduled for 2000 • Requirements Document Published Jan 2000 as W3C Note - has been revised based on comments received • 1st Public Working Draft on Data Model Published May 2000 • Currently working on Formal Algebra - Targeted for September 2000

  7. QL Status (3) • Currently about 60 members plus 5 Observers members - largest W3C Working Group • Weekly teleconference calls • Public working drafts every 3 months • One or more proposed recommendations is the goal • Have also developed a set of Usage Scenarios to validate data model and algebra - To be Published July 2000 with Revised Requirements Document

  8. QL Requirements • Possible multiple syntaxes - at least one expressed using XML - one must be human friendly • Defined independently of any protocol with which it is used • must not preclude possibility of Updates • must support real and “virtual “ XML documents • must support collections of documents

  9. Requirements (2) • Must support XML namespaces • must support datatypes from XML Schema • able to combine related elements from a single or multiple documents • Extensibility mechanism • provide access to document DTD or schema if available • operations on text must be applicable to text that spans element boundaries

  10. Requirements (3) • Support Internationalization • traverse inter and intra document references • preserve hierarchy and sequence of document structure in query results • have ability to transform XML structures and create new ones • Must not enforce any particular evaluation strategy • must be able to provide access to information derived from the environment in which the query was executed (I.e current time, date or user information)

  11. Potential Usage Scenarios Defined in Requirements Doc • XML Document search and management • XML processing of DBMS data • Integration of Multiple XML Sources • Filtering Streams of XML data

  12. Usage Cases Developed by WG • Each focuses on a specific application area • Each one contains sample DTD and data • Each one contains sample queries • Goal is to use them to validate data model, algebra and syntax’s • Living document - new uses cases can be submitted

  13. Usage Cases • Access to Relational Databases • Text Retrieval • Use of XML Namespaces • Use Cases based on some Sample Query Protocols Developed in Research Community • Use of References and IDREF • Preservation of Hierarchy and Sequence • Queries Based on Document Structure and Tagging

  14. Current Mention of Z39.50 • Usage Scenario Section- Following Text: • Queries may be used in many environments. For example a query might be embedded in a URL, an XML page, or a JSP or ASP page; represented by a string in a program written in a general purpose programming language; provided as an argument on the command-line or standard input; or supported by a protocol such as DASL or Z39.50

  15. Liaison Section • Several Other W3C Working Groups • DOM, XNL Schema, XSL, XPointer, XML Fragment, Internationalization Working Group, XML Fragment • IETF DASL - Language Reads: • XML Query must strive for smooth interaction with the IETF DASL (DAV Searching and Locating) Working Group, in such a way that the XML Query Language can be easily incorporated into the DASL Protocol

  16. QL Liaison with Z39.50 • Proposed language similar to that for DASL • Decision made not to do this - DASL language was their because they had deferred their query language to QL WG - For Z39.50 (and other communities like SQL) it was felt the way to go was to make sure those communities were kept informed and their input was solicited -Chair agreed to work me on this for the ZIG

  17. Relationship to Z39.50 • Conservative: Possible new Query Type in Existing Z39.50 protocol • Radical: Basis for a total restructuring of Z39.50 functionality with XML Query Language as the core - what this would look like would need to be defined

  18. Publicly Available Documents • Requirements Document http://www.w3.org/TR/xmlquery-req • Public Draft of Data Model • http://www.w3.org/TR/query-datamodel/

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