technology for e-commerce overview xml fall 2000c.watters2 outline introduction history and overview...

Technology for e-Commerce

Overview

XML

Fall 2000C.Watters 2

Outline

• Introduction• History and Overview• Show me the Code!• Applications• Protocols• Conclusions


Introduction

What is XML?• eXtensible Markup Language• Related to both SGML and HTML

“XML is like HTML with the training wheels off”-Dan Connolly, leader of XML activity at W3C


XMLUses tags to identify semantics of data• looks like HTML, but isn’t<slide><title>Introduction</title> <author><first>Carolyn</first>

<last>Watters</last> </author>

<content>XML this and that</content></slide>• is license free, platform-independent and well-

supported


SGML-HTML-XML??

The great ancestor of markup languages

SGML (Standardized General Markup Language)

Grammar is implemented using <tag>data</tag>

Grammar is defined by a Data Type Definition (DTD)

XML & HTML are cousins!


<HTML>

<TITLE>Statistics Canada</TITLE>

<BODY>

<H3>Welcome to Stats Canada</H3>

Statistics Canada ……. . <p> We like numbers…..

<img src=“mapleleaf.gif>

<ul>What we do

<li><a href=“census.html”>Census</a>

<li><a href=“special.html”>Special surveys</a>

<li>a href=“online.html”>Online data</a>

</ul>

</BODY>

</HTML>


HTMLHTML - Advantages• Simple - fixed set of tags• Portable - used with all browsers• Linking - within and to external documents

HTML - Disadvantages• Limited tag set• Can’t separate the definition from content• Can’t define structure of contents


XML

XML allows anyone to define a document structure separate from its display structure

• Explicit Definition - DTD


Some CodeSome Code

Schema• Entity

– Passport Details

• SubEntities– Last Name– First Name– Address

• Entity– Address

• SubEntities– Street– City– Town– State– Province– ……..


<!ELEMENT passport_details (last_name,first_name+,address)>

<!ELEMENT last_name (#PCDATA)>

<!ELEMENT first_name (#PCDATA)>

<!ELEMENT address (street,(city|town),(state|province),(ZIP|postal_code),country,contact_no?,email*)>

<!ELEMENT street (#PCDATA)>

<!ELEMENT city (#PCDATA)>

<!ELEMENT town (#PCDATA)>

<!ELEMENT state (#PCDATA)>

<!ELEMENT province (#PCDATA)>

<!ELEMENT ZIP (#PCDATA)>

<!ELEMENT postal_code (#PCDATA)>

<!ELEMENT country (#PCDATA)>

<!ELEMENT phone_home (#PCDATA)>

<!ELEMENT email (#PCDATA)>

DTD


Internal DTD and InstanceInternal DTD and Instance

<?xml version='1.0'?>

<!DOCTYPE passport_details [

<!ELEMENT passport_details (last_name,first_name+,address)>

<!ELEMENT last_name (#PCDATA)>

<!ELEMENT first_name (#PCDATA)>

<!ELEMENT address (street,(city|town),(state|province)

,(ZIP|postal_code),country,contact_no?,email*)>

<!ELEMENT street (#PCDATA)>

<!ELEMENT city (#PCDATA)>

<!ELEMENT town (#PCDATA)>

<!ELEMENT state (#PCDATA)>

<!ELEMENT province (#PCDATA)>

<!ELEMENT ZIP (#PCDATA)>

<!ELEMENT postal_code (#PCDATA)>

<!ELEMENT country (#PCDATA)>

<!ELEMENT phone_home (#PCDATA)>

<!ELEMENT email (#PCDATA)>

]>

<passport_details>

<last_name>Smith</last_name>

<first_name>Jo</first_name>

<first_name>Stephen</first_name>

<address>

<street>1 Great Street</street>

<city>GreatCity</city>

<state>GreatState</state>

<postal_code>1234</postal_code>

<country>GreatLand</country>

<email>[email protected]</email>

</address>

</passport_details>


Shared DTDShared DTD

XML Document specifies the DTD<?xml version='1.0'?>

<!DOCTYPE passport_details SYSTEM "PassportExt.dtd">

<passport_details>

<last_name>Smith</last_name>

<first_name>Jo</first_name>

<first_name>Stephen</first_name>

<address>

<street>1 Great Street</street>

<city>GreatCity</city>

<state>GreatState</state>

<postal_code>1234</postal_code>

<country>GreatLand</country>

<email>[email protected]</email>

</address>

</passport_details>


XML into HTML

• Need to convert XML tags into appropriate HTML tags for use in a browser!!

• <lastname>Smith</lastname>

• <b>Smith</b>


CSS and XSL

• CSS - Cascading Style Sheets– can predefined HTML display (font etc)– these are shared and reused

• XSL - XML Style language– predefine display characteristics for XML

entities– transform into CSS for browsers to use


Cascading Style SheetsCascading Style Sheets

CSSlast_name

{

font-family: verdana, arial;

font-size: 15pt;

font-weight:bold;

display: block;

margin-bottom: 5pt;

}

first_name

{


font-size: 15pt;

font-weight:bold;

display: block;

margin-bottom: 5pt;

}

street, city, town, state, province, ZIP, postal_code

{


font-size: 12pt;

font-weight:bold;

color:green;

display:block;

margin-bottom: 20pt;

margin-top: 40pt;

}

email

{


font-size: 12pt;

font-weight:bold;

color:blue;

display:block;

margin-top: 5pt;}


<?xml version='1.0'?>

<xsl:stylesheet

xmlns:xsl="http://www.w3.org/TR/WD-xsl"

xmlns="http://www.w3.org/TR/REC-html40"

result-ns="">

<xsl:template><xsl:apply-templates/></xsl:template>

<xsl:template match="/">

<html>

<head>

<title><xsl:value-of select="/passport/last_name"/></title>

</head>

<body>

<H1><xsl:value-of select="/pastport/last_name, first_name"/></H1>

<H2>Address</H2>

<BLOCKQUOTE>

<xsl:apply-templates select="/passport/address"/>

</BLOCKQUOTE>

</body>

</html>

XSL (Style Language)


• Coordinating Heterogenous Databases

• Separation of Structure / Content / Display

• Document Validity Checking

• Potential Use in Standards

Importance of XML


Example

Boeing

• Boeing places a DTD on its site

• part purchasers use this DTD

• Boeing can use multiple XSL stylesheets


Boeing (cont’d)

• customer creates an order document, they can verify the validity of that document against the DTD.

• this ensures they are transmitting only type-valid orders.

• in turn, Boeing can ensure they are receiving only type-valid documents.


Examples of Evolving Industry XML Standards

• XML/EDI• Open Financial Exchange (OFE)• Open Trade Protocol (OTP)

• HL7 (Health Level 7) Kona Proposal

• Resource Description Format (RDF)

Industry-wide DTDsIndustry-wide DTDs


• A unified specification for the electronic exchange of financial data between financial institutions, businesses and consumers via the Internet.

• Supports consumer and small business banking, bill payment, bill presentment and investments, including stocks, bonds, and mutual funds.

Open Financial Exchange


• Global Standard for all forms of trade on the Internet

• Provides consistent consumer purchasing experience regardless of the payment instrument or software and hardware product used.

• Specifies how Internet transactions can occur, independent of the method of payment

Open Trade Protocol


• Differs from Secure Electronic Transaction (SET).

• OTP complements, but does not replace other protocols.

• Provides consumers with a record of purchases for tax purposes, make expense claims, etc.

• Provides the same factual transaction for the virtual world.

Open Trading Protocol

<!DOCTYPE Transaction [

<!ELEMENT Payment (CredCardPay / OtherPay),

Amount, Payer, Payee)

<!ELEMENT CredCardPay (Cardtype, CardNo, Expdate, CardHolder)

<!ELEMENT OtherPay ANY

<!ELEMENT Amount (CredCardPay / OtherPay), Amount, Payer, Payee)

<!ELEMENT Payer (Email, (Name)?, Address)?)

OTP DTD


• In the major Web Browser products.• In Microsoft Office 2000.• In every major database tool by end of 2000.• In every HTML tool by end of 2000.• CommerceNet believes that XML may just be

the “killer application” needed to open up the Worldwide Web for Electronic Commerce.

Is this for real?


XML - Advantages• Platform and system independent• User-defined tags• Doesn’t require explicit DTD• Display format and content are separate

XML - Disadvantages• Requires a processing application• “Pickier” than HTML• Must be converted to HTML to view in browser

Summary


• W3 Consortium: www.w3.com

• kazillions of XML books in every bookstore!

Resources

technology for e-commerce overview xml fall 2000c.watters2 outline introduction history and overview...

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