28 October 2008 CIS 340# 1

Topics• To define XML as a technology• To place XML in the context of

system architectures

Online support:http://www.w3schools.com/xml/default.asp

Online community:http://www.oasis-open.org/home/index.php

Standards development:http://www.oasis-open.org/committees/committees.php#completed

28 October 2008 CIS 340# 2

Spectrum of “Technologies”

XPATH

DTD

XSD

XMLXSL

XSLT

XSL-FOXFORMS

XLINK

XQUERY

XPOINTER

XML

• XML stands for eXtensible Markup Language.• XML is designed to transport and store data.• XML is important to know, and very easy to learn.

28 October 2008 CIS 340# 3

28 October 2008 CIS 340# 4

XML ...

• Is a syntax for describing data– Almost any data

• Produces “vocabularies”– Anyone can produce an individualized

vocabulary– Sharing the vocabulary enables the

sharing of data

Organizational hub– http://www.xml.org/

28 October 2008 CIS 340# 5

XML History• Shares similar historical roots with HTML• Part of SGML (Standard Generalized

Markup Language – 1970s)

• HTML describes how to renderdescribes how to render information via a browser– “rendering” options are fixed via the language– Display potential fixed via the selected output

technology

HTML limitation?» Interpretation after transmission (e.g. useuse) requires human intervention

28 October 2008 CIS 340# 6

XML History (p. 2)

• XML enables human bypass• XML offers self-descriptive

labels equating to interpretation

• XML provides “meta information”

If XML used, Company B can:

•Have programs manipulate data

•Import data directly to database

•Store immediately within similar,

affiliated documents

•Manipulate data for specific needs

•continues....COMPANY A

COMPANY BFINANCIAL.rpt

A-WEB

28 October 2008 CIS 340# 7

Vocabularies

• Collection of elements• Not predefined• But related into a structure vocabularyvocabulary

• ““Instance of”Instance of” XML document

Def:Def:

28 October 2008 CIS 340# 8

Sample Defined Vocabularies (in progress)

• Accounting XML

• Advertising XML

• Astronomy XML

• Building XML

• Chemistry XML

• Construction XML

• Education XML

• Food XML

• Finance XML

• Government XML

• Healthcare XML

• Human Resources XML

• Instruments XML

• Insurance XML

• Legal XML

• Manufacturing XML

• News XML

• Photo XML

• Physics XML

• Publishing XML

• Real Estate XML

• Telecommunications XML

• Travel XML

28 October 2008 CIS 340# 9

EX: Address Vocabulary

Contents of the files? .../xml/...

28 October 2008 CIS 340# 10

XML Document• Prolog

– (optional)

– Describes the xml-specification

– Declares the document type (DTD)

• Body– (required)– collection of instantiated

vocabulary terms

• Epilog– (optional)– processing or comments

<?xml version = 1.0”?>

<!DOCTYPE book SYSTEM “book.dtd”>

<book category = “FICTION”>

<title>Golden Phoenix</title>

<author>J. K. Rowling</author>

</book>

<book category = “NON-FICTION”>

<title>Mythical Work</title>

<author>E. Yourdan</author>

</book>

28 October 2008 CIS 340# 11

Schemas» Document Type Definition (DTD)

» XML Schema Definition (XSD)

• Offers the legal structure of the elements of a vocabulary

• Enables the programmatic access of an XML “document”

• Meaning?• Declare element types• Qualify elements with attributes• Define parent-child relationships• Assign simple data types• Establish validation basis for data acceptance

DTD

28 October 2008 CIS 340# 12

!DOCTYPE note defines that the root element of this document is note!ELEMENT note defines that the note element contains four elements: to,from,heading,body"!ELEMENT to defines the to element  to be of type "#PCDATA"!ELEMENT from defines the from element to be of type "#PCDATA"!ELEMENT heading defines the heading element to be of type "#PCDATA"!ELEMENT body defines the body element to be of type "#PCDATA"

28 October 2008 CIS 340# 13

EX: DTD Specification

<!DOCTYPE book [

<!ELEMENT book (title, author)>

<!ATTLIST book CATEGORY (Fiction |Non-Fiction)>

<!ELEMENT title (#PCDATA)>

<!ELEMENT author (#PCDATA)>

]>

EX: XSD Specification

(see p. 29)

address example

<?xml version = “1.0”?><xsd:schema xmlns:xsd=

http://www.w3.org/2001/XMLSchema><xsd:element name=“book”>

<xsd:complexType><xsd:sequence>

<xsd:element name=“title” type “xsd:string”/>

<xsd:element name=“author” type “xsd:string”/>

</xsd:sequence><xsd:attribute name = “category”>

<xsd:simpleType><xsd:restriction base=“xsd:string”/> <xsd:enumeration value = “Fiction”/> <xsd:enumeration value = “Non-Fiction”/></xsd:restriction>

</xsd:simpleType></xsd:attribute>

</xsd:complexType></xsd:element></xsd:schema>

28 October 2008 CIS 340# 15

XQUERY ... FLWR (“flower”)

• Query language

• aka SQL

• Designed for XML documents

• Allows for logic to be used to access embedded information of XML documents

28 October 2008 CIS 340# 16

XQUERY ... FLWR (“flower”)FLWR :: For Let Where Return General versions:

for Variable in Exp for Variable in Exp where Exp where Exp return Exp sortby(Exp)return Exp sortby(Exp)

let Variable := Exp let Variable := Exp where Exp where Exp

return Exp sortby(Exp)return Exp sortby(Exp)

for $x in document (“books.xml”) // bookfor $x in document (“books.xml”) // bookwhere $x/author = “J. K. Rowling”where $x/author = “J. K. Rowling”return $x/titlereturn $x/title

givesgives<title>Golden Phoenix</title><title>Golden Phoenix</title>

28 October 2008 CIS 340# 17

Connective LanguagesXSLT• XML XML SStylesheet

LLanguage TTransformations

• Mechanism for taking XML documents to different output renditions

XPATH• Collection of “utility

functions”• Enables the parsing

and traversing of XML structures

• Required mechanism for XSLT and XQUERY

Not defined via an XML-compliant syntax

Most XML languages are

28 October 2008 CIS 340# 18

Highlights

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