XML Query Working Group Charter
The mission of the XML Query Working Group, part of the Extensible Markup Language (XML) Activity, is to provide flexible query facilities to extract data from XML and virtual documents, such as contents of databases or other persistent storage that are viewed as XML via a mapping mechanism, on the Web.
| End date | 31 January 2009 |
|---|---|
| Confidentiality | Proceedings are Member-only |
| Initial Chairs | Andrew Eisenberg, Jim Melton |
| Initial Team Contacts (FTE %: 35) |
Liam Quin |
| Usual Meeting Schedule | Telcons: Weekly Ftf: 5-6 per year |
Scope
The functionality of the XML Query language encompasses selecting whole documents or components of documents based on specified selection criteria, as well as constructing XML documents from selected components.
The goal of the XML Query Working Group is to produce and maintain a formal data model for XML documents with namespaces (based on the XML Information Set), a set of query operators on that data model (a so-called algebra), and then a query language with a concrete canonical syntax based on the proposed operators. The queries allowed by the query language should be computable and terminating. Such queries will act on fixed collections of XML documents. Functionalities include full-text text search (as opposed to simple substring search) or update instances of the query data model.
The Working Group may also work on a set of XQuery Scripting Extensions intended to facilitate the use of XML Query in developing applications. A paper in this area has been published, XQueryP: Programming with XQuery, but the Working Group must produce Use Cases and Requirements before proceeding.
Success Criteria
The Working Group expects to demonstrate at least 2 interoperable implementations of all required and optional features of any new Specification before requesting to advance to Proposed Recommendation.
Deliverables
Jointly with the XSL Working Group, a set of W3C Recommendations for:
- XQuery 1.0 and XPath 2.0 Data Model (XDM)
- XQuery 1.0 and XPath 2.0 Functions and Operators
- XML Query 1.0 and XPath 2.0 Full-Text
- XQuery 1.0 and XPath 2.0 Formal Semantics
- XSLT 2.0 and XQuery 1.0 Serialization
- XML Path Language (XPath) 2.0
A set of W3C Recommendations for:
- XML Syntax for XQuery 1.0 (XQueryX)
- XQuery 1.0: An XML Query Language
- XML Syntax for XQuery 1.1 (XQueryX)
- XQuery 1.1: An XML Query Language
- XQuery Update Facility
- XQuery Scripting Extensions
Jointly with the XSL Working Group, if needed to support features in XQuery 1.1, the Working Group will produce W3C Recommendations for:
- XQuery 1.1 and XPath 2.1 Data Model (XDM)
- XQuery 1.1 and XPath 2.1 Functions and Operators
- XQuery 1.1 and XPath 2.1 Formal Semantics
- XSLT 2.1 and XQuery 1.1 Serialization
- XML Path Language (XPath) 2.1
Note: The XSL and XML Query Working Group have compiled a list of Candidate requirements for XQuery 1.1 and XPath 2.1. This is not meant to be an exhaustive list of such features. The XML Query Working Group must publish an XML Query 1.1 Requirements document before working on XQuery 1.1 and related documents. Similarly, the XML Query Working Group must publish use cases and requirements documents for the XQuery Scripting Extensions before doing further work in that area. In addition, the Requirements and Use Cases for XML Query 1.1 must be published before any work is started on Scrpiting Extensions, in case there are interactions between the two paths of work.
The following documents will become Working Group Notes:
- XML Query (XQuery) Requirements
- XML Query Use Cases
- XQuery and XPath Full-Text Requirements
- XQuery and XPath Full-Text Use Cases
- XML Query 1.1 (XQuery 1.1) Requirements
- XPath Requirements Version 2.0
- XPath Requirements Version 2.1
- XQuery Update Facility Requirements
- XQuery Update Facility Use Cases
- Building a Tokenizer for XPath or XQuery
- XQuery Scripting Extensions Use Cases
- XQuery Scripting Extensions Requirements
Other Deliverables
The following additional items will be developed and/or maintained by the XML Query Working Group:
- An interoperability test suite for XQuery 1.0, to promote interoperability.
- An interoperability test suite for XQuery Full-Text: intended to assess the accuracy of the Candidate Recommendations, and to promote interoperability.
- An interoperability test suite for XQuery Update Facility: intended to assess the accuracy of the Candidate Recommendations, and to promote interoperability.
- An interoperability test suite for the XML Query Scripting Extensions, to promote interoperability, and to demonstrate the implementability of the specification.
Milestones
| Specification | FPWD | LC | CR | PR | Rec |
|---|---|---|---|---|---|
| Note: The group will document significant changes from this initial schedule on the group home page. | |||||
| XQuery 1.0 and XPath 2.0 Data Model | N/A | N/A | N/A | N/A | January 2007 |
| XQuery 1.0 and XPath 2.0 Functions and Operators | N/A | N/A | N/A | N/A | January 2007 |
| XQuery 1.0 and XPath 2.0 Formal Semantics | N/A | N/A | N/A | N/A | January 2007 |
| XSLT 2.0 and XQuery 1.0 Serialization | N/A | N/A | N/A | N/A | January 2007 |
| XML Path Language (XPath) 2.0 | N/A | N/A | N/A | N/A | January 2007 |
| XQuery 1.0 | N/A | N/A | N/A | N/A | January 2007 |
| XML Query 1.0 and XPath 2.0 Full-Text | (October 2006) | February 2007 | May 2007 | September 2007 | January 2008 |
| XQuery Update Facility | (October 2006) | February 2007 | July 2007 | September 2007 | January 2008 |
| XQuery 1.1 | July 2007 | April 2008 | September 2008 | January 2009 | March 2009 |
| XQuery Scripting Extensions | August 2007 | May 2008 | November 2008 | March 2009 | May 2009 |
Timeline View Summary
- October 2006: XQuery and XPath Full-Text WD, XQuery Update Facility WD
- January 2007: XQuery 1.0 and XPath 2.0 Data Model REC, XQuery 1.0 and XPath 2.0 Functions and Operators REC, XSLT 2.0 and XQuery 1.0 Serialization REC, XQuery 1.0 and XPath 2.0 Formal Semantics REC, XML Path Language XPath 2.0 REC, XQuery 1.0 REC
- February 2007: XQuery and XPath Full-Text LC, XQuery Update Facility LC
- May 2007: XQuery 1.1 Requirements WD; XQuery Update Facility CR; XQuery and XPath Full-Text CR
- July 2007: XQuery 1.1 WD
- August 2007: XQuery Scripting Extensions FPWD
- September 2007: XQuery and XPath Full-Text PR, XQuery Update Facility PR
- January 2008: XQuery and XPath Full-Text REC, XQuery Update Facility REC
- April 2008: XQuery 1.1 LC
- May 2008: XQuery Scripting Extensions LC
- September 2008: XQuery 1.1 CR
- November 2008: XQuery Scripting Extensions CR
- January 2009: XQuery 1.1 PR
- March 2009: XQuery Scripting Extensions PR
- March 2009: XQuery 1.1 REC
- May 2009: XQuery Scripting Extensions REC
Dependencies
W3C Groups
- XSL
- The XPath 1.0 language was jointly developed by the XSL Working Group. The XML Query Working Group will collaborate with the XSL Working Group to extend XPath 1.0 to an XPath 2.0 (and possibly an XPath 2.1) that covers the functionality that is common to both XML Query and XSLT. The groups will collaborate on additional documents that support both XQuery 1.0 and XPath 2.0 (and XQuery 1.1 and XPath 2.1) starting by gathering requirements.
- XML Schema
- It is a goal of the XML Query work to be compatible with the work of the XML Schema Working Group on XML Schema Part 2: Datatypes (XML Schema Part 2) and XML Schema Part 1: Structures (XML Schema Part 1). For example, it should be possible to base query predicates on the existing DTD or XML Schema Part 1 definition of the content of an XML document and on the data types defined as part of W3C XML Schema Part 2.
- XML Core
- The XML Query work will define a formal data model of XML documents. This model must be based on the model of the XML Infoset (XML Information Set). In case incompatibilities arise, requirements must be posed to the XML Core Working Group. In any case, the final model used by the XML Query working group will have to be based on, and totally compatible with, the model of the XML Infoset. In addition any XML Query definition of an XML fragment will take into consideration the XML Fragment Interchange specification (XML Fragment Interchange)
- Internationalization Working Group
- It is a goal of the XML Query work to ensure proper internationalization of the XML Query technology. The mission and scope of the Internationalization Working Group is to propose and coordinate any techniques, conventions, guidelines and activities within the W3C that help to make and keep the Web international. The XML Query Working Group and the Internationalization Working Group will work together to agree on specific I18N requirements and find solutions.
There are no requirements for co-development of features with the following Working Groups, but there are points of contact between their work and that of this Working Group, and thus logical dependency between their deliverables and those of this Working Group. Requirements from these Working Groups are expected to be well suited for communication via documents:
- WAI Protocols & Formats Working Group
- Reuse of common constructs greatly facilitates accessibility; the WAI PF Working Group will review work on the XML query facilities to be sure cost/benefit design decisions are informed of the benefits of accessibility.
- RDF Data Access Working Group
- The relationship with XQuery section mentions that the RDF DAWG should aim to maximize W3C technology re-use, such as using the XQuery 1.0 and XPath 2.0 Functions and Operators specification. The RDF Data Access Working Group and the XML Query Working Group will coordinate to ensure the reusability of the XQuery/XPath technologies.
When approved by the XML Coordination Group, liaison with other W3C Working Groups can be accomplished through joint task forces. It is expected that this be required for liaison with at least the XML Schema, XSL and Internationalization Working Groups.
Participation
To be successful, the XML Query Working Group is expected to have 8 or more active participants for its duration. Effective participation to XML Query Working Group is expected to consume half of a work day per week for each participant; two days per week for editors. The XML Query Working Group will allocate also the necessary resources for building Test Suites for each specification.
Participants are reminded of the Good Standing requirements of the W3C Process.
Communication
This group primarily conducts its work on the Member-only mailing list
w3c-xml-query-wg@w3.org (archive), as
well as various other lists: w3c-xsl-query@w3.org (archive), member-query-fttf@w3.org
(archive)
and member-query-test@w3.org
(archive).
Public feedback happens through public-qt-comments@w3.org (archive).
Information about the group (deliverables, participants, face-to-face meetings, teleconferences, etc.) is available from the XML Query Working Group home page.
Patent Policy
This Working Group operates under the W3C Patent Policy (5 February 2004 Version). To promote the widest adoption of Web standards, W3C seeks to issue Recommendations that can be implemented, according to this policy, on a Royalty-Free basis.
For more information about disclosure obligations for this group, please see the W3C Patent Policy Implementation.
About this Charter
This charter for the XML Query Working Group has been created according to section 6.2 of the Process Document. Except as specified in this charter, the Working Group follows the Common Procedures for XML Working Groups. In the event of a conflict between this document, the common procedures, or the provisions of any charter and the W3C Process, the W3C Process shall take precedence.
Please also see the previous charter for this group.
Liam Quin, XML Activity lead
Philippe Le Hégaret, Architecture Domain Leader
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$Date: 2007/01/26 17:44:48 $