XQuery: A Language for Querying XML Data, Slides of Database Programming

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XQUERY

(XML QUERY)

STUDENT NAME: MEHMET AKİF YÜCEL STUDENT ID: 2013400063 INSTRUCTOR: TAFLAN GÜNDEM CMPE 422 PRESENTATİON

Content of the Lesson

 What is XQuery?  What is the mission of XQuery?  What are its applications?  What are different versions and their historical development?  What is XDM and its relation with XQuery?  What are XQuery extensions?  How we implement XQuery?

XQUERY

 A language for querying XML data  XQuery for XML is like SQL for databases  XQuery is built on XPath expressions  XQuery is supported by all major databases  XQuery is a W3C Recommendation

APPLICATIONS OF XQUERY

 Extract information to use in a Web Service  Generate summary reports  Transform XML data to XHTML  Search Web documents for relevant information



XQuery 1.0 became a W3C Recommendation on

January 23, 2007.



XQuery 3.0 became a W3C Recommendation on

April 8, 2014.



XQuery 3.1 became a W3C Recommendation on

March 21, 2017.

 (^) The World Wide Web Consortium ( W3C ) is the main international standards organization for the World Wide Web. Versions

 Sequences  Items  XQuery/XPath sequences differ from lists in languages like Lisp and Prolog by excluding nested sequences.

 XQuery provides the means to extract and manipulate data from XML documents or any data source that can be viewed as XML, such as relational databases or office documents.

XDM

 (^) XDM calls XQuery and XPath Data Model.  (^) It is the data model shared by the XPath 2.0, XSLT 2.0 and XQuery programming languages. It is a W3C recommendation and forms an integral part of all three languages.  (^) Originally, it was based on the XPath 1.0 data model which in turn is based on the XML Information Set .  (^) You can see The XDM type hierarchy on the right.

XDM

 All values as sequences.  The items are in a sequence.  Items either be XML nodes or atomic values.  Atomic values may be integers, strings, booleans, and so on.

XQUERY EXTENSIONS

 XQuery 3.0 was abandoned for lack of resources.  Work on XQuery 3.0 was published as a Recommendation on 8 April 2014, and XQuery 3.1 is a Recommendation as at February 2017.  A scripting (procedural) extension for XQuery was designed, but never completed.

XQUERY EXTENSIONS

 (^) The EXPath Community Group develops extensions to XQuery and other related standards (XPath, XSLT, XProc, and XForms). The following extensions are currently available:  (^) Packaging System  (^) File Module  (^) Binary Module  (^) Web Applications

CODING

 Functions  Path Expressions  Predicates  FLWOR  Select Nodes with FLWOR

Functions

 XQuery uses functions to extract data from XML documents.  The doc() function is used to open the "books.xml" file:  doc("books.xml")