W3C XML Query Language WG

W3C XML Query Language WG Mark Needleman DRA ZIG Tutorial January 19, 2000

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

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 scheduled for early February

QL Status (2) • Currently about 55 members - largest W3C Working Group • Weekly teleconference calls • Requirements document being finalized - will be submitted as a W3C Note • Public working drafts every 3 months • One or more proposed recommendations is the goal

Potential 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

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

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)

Potential Usage Scenarios • XML Document search and management • XML processing of DBMS data • Integration of Multiple XML Sources • Filtering Streams of XML data

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

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

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

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

W3C XML Query Language WG