standards in information management xml

XDR XML Data Reduced An earlier XML schemaCSS Cascading Style Sheets Allows you to specify styles XSL Extensible Stylesheet Language Language for expressing stylesheets; consists of XS

Standards in Information

Management: XML

Arijit Sengupta

Learning Objectives

• Learn what XML is

• Learn the various ways in which XML is used

• Learn the key companion technologies

• See how XML is being used in industry as a language

Agenda

• Overview

• Syntax and Structure

• The XML Alphabet Soup

• XML as a meta-language

Overview

What is XML?

• A tag-based meta language

• Designed for structured data representation

• Represents data hierarchically (in a tree)

• Provides context to data (makes it meaningful)

Overview

XML and Structured Data

• Pre-XML representation of data:

• XML representation of the same data:

1234”,”CUST001”,”X9876”,”5”,”14.98

“PO-”

<PURCHASE_ORDER>

<PO_NUM> PO-1234 </PO_NUM>

<CUST_ID> CUST001 </CUST_ID>

<ITEM_NUM> X9876 </ITEM_NUM>

<QUANTITY> 5 </QUANTITY>

<PRICE> 14.98 </PRICE>

</PURCHASE_ORDER>

Agenda

• Overview

• Syntax and Structure

• The XML Alphabet Soup

• XML as a meta-language

<ELEMENT3 type=‘string’> </ELEMENT3>

<ELEMENT4 type=‘integer’ value=‘9.3’> </ELEMENT4>

</ROOT>

Elements

Elements with Attributes

Syntax and Structure

Rules For Well-Formed XML

• There must be one, and only one, root element

• Sub-elements must be properly nested

 A tag must end within the tag in which it was

started

• Attributes are optional

 Defined by an optional schema

• Attribute values must be enclosed in “” or ‘’

• Processing instructions are optional

• XML is case-sensitive

 <tag> and <TAG> are not the same type of

element

Syntax and Structure

Namespaces: Overview

• Part of XML’s extensibility

• Allow authors to differentiate between tags of the

same name (using a prefix)

Frees author to focus on the data and

decide how to best describe it

Allows multiple XML documents from multiple

authors to be merged

• Identified by a URI (Uniform Resource Identifier)

When a URL is used, it does NOT have to

represent

a live server

Namespace declaration examples:

Namespace declaration Prefix URI (URL)

xmlns: bk =

“http://www.example.com/bookinfo/”

Syntax and Structure

Namespaces: Default Namespace

• An XML namespace declared without a prefix becomes

the default namespace for all sub-elements

• All elements without a prefix will belong to the default namespace:

<BOOK

xmlns=“http://www.bookstuff.org/bookinfo”> <TITLE>All About XML</TITLE>

<AUTHOR>Joe Developer</AUTHOR>

Syntax and Structure

Namespaces: Attributes

• Unqualified attributes do NOT belong to any namespace

 Even if there is a default namespace

• This differs from elements, which belong to the default

namespace

• You can define your own entities

• Parsed entities can contain text and markup

• Unparsed entities can contain any data

 JPEG photos, GIF files, movies, etc.

Entity Substitution

&lt; <

&amp; &

Agenda

• Overview

• Syntax and Structure

• The XML Alphabet Soup

• XML as a meta-language

The XML ‘Alphabet Soup’

• XML itself is fairly simple

• Most of the learning curve is knowing about

all of the related technologies

XDR XML Data Reduced An earlier XML schema

CSS Cascading Style Sheets Allows you to specify styles

XSL Extensible Stylesheet

Language Language for expressing stylesheets; consists of XSLT and

XSL-FO XSLT XSL Transformations Language for transforming XML

documents XSL-FO XSL Formatting Objects Language to describe precise layout

of text on a page

The XML ‘Alphabet Soup’

XPath XML Path Language A language for addressing parts of

an XML document, designed to be used by both XSLT and XPointer XPointer XML Pointer

Language Supports addressing into the internal structures of XML

documents XLink XML Linking

Language Describes links between XML documents XQuery XML Query Language

(draft) Flexible mechanism for querying XML data as if it were a database DOM Document Object

Model API to read, create and edit XML documents; creates in-memory

object model SAX Simple API for XML API to parse XML documents;

event-driven Data Island XML data embedded in a HTML page

Data Automatic population of HTML elements from XML data

 Supports data types

 Current standard recommended by W3C

 More restrictive than well-formed XML

• Define which elements are present and

in what order

• Define the structural relationships of elements

<!ELEMENT BOOK (TITLE+, AUTHOR) >

<!ELEMENT TITLE (#PCDATA) >

<!ELEMENT AUTHOR (#PCDATA) >

The XML ‘Alphabet Soup’

Schemas: Why You Should Use XSD

• Newest W3C Standard

• Broad support for data types

• Reusable “components”

 Simple data types

 Complex data types

• Extensible

• Inheritance support

• Namespace support

• Ability to map to relational database tables

• XSD support in Visual Studio.NET

The XML ‘Alphabet Soup’

Transformations: XSL

• Language for expressing document styles

• Specifies the presentation of XML

 More powerful than CSS

The XML ‘Alphabet Soup’

Transformations: Overview

• XSLT – a language used to transform XML data into a

different form (commonly XML or HTML)

XML, HTML,

… XML

XSLT

The XML ‘Alphabet Soup’

Transformations: XSLT

• The language used for converting XML

documents into other forms

• Describes how the document is transformed

• Expressed as an XML document (.xsl)

• Template rules

Patterns match nodes in source document

Templates instantiated to form part of result document

• Uses XPath for querying, sorting, etc.

The XML ‘Alphabet Soup’

XPath (XML Path Language)

• General purpose query language for identifying nodes in

an XML document

• Declarative (vs procedural)

• Contextual – the results depend on current node

• Supports standard comparison, Boolean and

mathematical operators (=, <, and, or, *, +, etc.)

The XML ‘Alphabet Soup’

XPath Operators

Operator Usage Description

/ Child operator – selects only immediate children

(when at the beginning of the pattern, context is root)// Recursive descent – selects elements at any depth

(when at the beginning of the pattern, context is root) Indicates current context

Selects the parent of the current node

* Wildcard

@ Prefix to attribute name (when alone, it is an attribute

wildcard)[ ] Applies filter pattern

The XML ‘Alphabet Soup’

XPath Query Examples

./author (finds all author elements within current context) /bookstore (find the bookstore element at the root)

/* (find the root element)

//author (find all author elements anywhere in document)

More XPath Examples

Path Expression Result

/bookstore/book[1] Selects the first book element that is the child of the

bookstore element /bookstore/book[last()] Selects the last book element that is the child of the

bookstore element /bookstore/book[last()-1] Selects the last but one book element that is the child of

the bookstore element /bookstore/book[position()<3] Selects the first two book elements that are children of the

bookstore element //title[@lang] Selects all the title elements that have an attribute named

lang //title[@lang='eng'] Selects all the title elements that have an attribute named

lang with a value of 'eng' /bookstore/book[price>35.00] Selects all the book elements of the bookstore element

that have a price element with a value greater than 35.00

/bookstore/book[price>35.00]/title Selects all the title elements of the book elements of the

bookstore element that have a price element with a value greater than 35.00

XPath Functions

• Accessor functions:

 node-name, data, base-uri, document-uri

• Numeric value functions:

 abs, ceiling, floor, round, …

• String functions:

 compare, concat, substring, string-length, uppercase, lowercase, starts-with, ends-with, matches, replace, …

• Other functions include functions on boolean values, dates, nodes, etc

The XML ‘Alphabet Soup’

Data Islands

• Can be embedded in an HTML SCRIPT element

• XML is accessible via the DOM:

<SCRIPT language=“xml” id=“XMLID”>

<SCRIPT type=“text/xml” id=“XMLID”>

<SCRIPT language=“xml” id=“XMLID”

src=“mydocument.xml”>

Join XML data with existing database tables

Update the database via XML Updategrams

New XML data type in SQL 2005

• Microsoft Exchange Server

XML is native representation of many types of

data

Used to enhance performance of UI scenarios

(for example, Outlook Web Access (OWA))

Agenda

• Overview

• Syntax and Structure

• The XML Alphabet Soup

• XML as a meta-language

WML

XQL

A Language to create Languages

GO

Gene Ontology (GO)

• Describing and manipulating information about the molecular function, biological process and cellular component of gene products

• Gene Ontology website:

 see sample documents here

 some require plug-in downloads, can be slow

Wireless ML

• Allows web pages to be displayed over mobile devices

• WML works with WAP to deliver the content

• Underlying model: Deck of Cards that the User can sift

Scalable Vector Graphics

• Describing vector graphics data for use over the web

• Rendering is done on the browser

• Bandwidth demands lower, scaling easier

 www.irt.org/articles/js176 1999 article and

good, brief tutorial

 planet.svg An Example from Deitel

Bean ML

• Describing software components such as Java Beans

• Defines how the components are interconnected and can be used

• Bean ML Specs and Tools

 www.alphaworks.ibm.com/aw.nsf/techmain/bml

• Bean ML Resources

 www.oasis-open.org/cover/beanML.html

 With Bean ML

• You can mark-up beans using Bean ML

• And invoke different operations on Beans

• Includes BML Scripting Framework

XBRL

• Extensible Business Reporting Language

• Capturing and representing financial and accounting information

• Variety of situations

 e.g publishing reports, extracting data for

analysis, regulatory forms etc.

• Initiated under the direction of AICPA

 See also Whitepapers link explaining how these can be used for

• E-procurement

• E-fulfillment

• And others

ebXML

• UN/CEFACT: the United Nations body whose mandate covers worldwide policy and technical development in the area of trade facilitation and electronic business

 Still needs buy-in from the larger IS/IT vendors

• Related Effort: RosettaNet

 http://www.rosettanet.org/rosettanet/Rooms/DisplayPages

/LayoutInitial

 Business Processes for IT, Component and Chip companies

Conclusion

• Overview

• Syntax and Structure

• The XML Alphabet Soup

• XML as a meta-language