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Module 1 Introduction and Motivation

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Title: Module 1 Introduction and Motivation


1
Module 1Introduction and Motivation
2
If I invent another programming language, its
name will contain the letter X.
(N. Wirth, Software Pioniere Konferenz, Bonn 2001)
3
Google Indicator
4
A history of Language
5
2 x (Descartes)
6
lx.2x (Church)
7
(LAMBDA (x) ( 2 x)) (McCarthy)
8
W3C
  • lt?xml version1.0gt
  • ltlambda-termgt
  • ltvarlistgt ltvargtxlt/vargtlt/varlistgt
  • ltexpressiongt ltapplicationgt
  • ltexprgtltconstgtlt/constgtlt/exprgt
  • ltarg-listgtltexprgtltconstgt2lt/constgtlt/exprgt
  • ltexprgtltvargtxlt/vargtlt/exprgt
  • lt/arg-listgt
  • lt/applicationgt lt/expressiongt
  • lt/lambda-termgt

9
What can the Web do for you?
  • Download show HTML Documents
  • Forms
  • Pre-compiled point queries
  • Updates in specific Web application
  • Everywhere, any time, platform independent
  • Simple keyword search (Google)
  • Good for human-human, human-machine communication
  • Scalability in the Millions of Users

10
What the Web cannot do?
  • Applications do not understand HTML
  • Machine-Machine communication difficult
  • Distributed Updates
  • Long transactions (business processes)
  • Powerful Queries
  • Where can I find a used car for CHF 1000
  • Scalability in the Millions of Machines

11
Design Principles of W3C
  • Everybody is autonomous
  • Everybody can participate (open)
  • All Standards are compatible
  • All Standards are downwards compatible
  • Platform- and vendor independance

12
A little bit of history
  • Database world
  • 1970 relational databases
  • 1990 nested relational model and object oriented
    databases
  • 1995 semi-structured databases
  • Documents world
  • 1974 SGML (Structured Generalized Markup
    Language)
  • 1990 HTML (Hypertext Markup Language)
  • 1992 URL (Universal Resource Locator)

Data documents information 1996 XML (Extended
Markup Language) URI (Universal Resource
Identifier)
13
What is XML?
  • The Extensible Markup Language (XML) is the
    universal format for structured documents and
    data on the Web.
  • Base specifications
  • XML 1.0, W3C Recommendation Feb '98
  • Namespaces, W3C Recommendation Jan '99

14
XML Data Example
  • ltbook year1967gt
  • lttitlegtThe politics of experience
  • lt/titlegt
  • ltauthorgt
  • ltfirstnamegtRonaldlt/firstnamegt
  • ltlastnamegtLainglt/lastnamegt
  • lt/authorgt
  • lt/bookgt

Elements
  • Syntax, no abstract model
  • Documents, elements and attributes
  • Tree-based, nested, hierarchically organized
    structure

15
XML vs. relational data
  • Relational data
  • Killer application banking industry
  • Invented as a mathematically clean abstract data
    model
  • Philosophy schema first, then data
  • Never had a standard syntax for data
  • Strict rules for data normalization, flat tables
  • Order is irrelevant, textual data supported but
    not primary goal
  • XML
  • First killer application publishing industry
  • Invented as a syntax for data, only later an
    abstract data model
  • Philosophy data and schemas should not be
    correlated, data can exist with or without
    schema, or with multiple schemas
  • No data normalization, flexibility is a must,
    nesting is good
  • Order may be very important, textual data support
    a primary goal

16
Reasons for the XML success
  • XML is a general data representation format
  • XML is human readable
  • XML is machine readable
  • XML is internationalized (UNICODE)
  • XML is platform independent
  • XML is vendor independent
  • XML is endorsed by the World Wide Web Consortium
  • XML is not a new technology
  • XML is not only a data representation format,
    its a full infrastructure of technologies

17
XML as a family of technologies
  • XML Information Set
  • XML Schema
  • XML Query
  • The Extensible Stylesheet Transformation Language
    (XSLT)
  • XLink, XPointer
  • XML Forms
  • XML Protocol
  • XML Encryption
  • XML Signature
  • Others
  • almost all the pieces needed for a good
    XML-based information hub

18
Overview of XML Technologies
  • W3C Standards
  • Data XML, Namespaces, Infoset, Schema
  • Communication SOAP, Encryption, WSDL, UDDI
  • Processing Xpath, XSLT, Xquery, Xupdate, Xquery
    Text
  • Integration RDF, OWL
  • Other Standards
  • Vertical domains RosettaNet, ebXML, ml
  • Workflow BPEL
  • Interfaces DOM, SAX, JAXP, SQL / XML

19
Motivation for XML
  • Data lives forever (longer than program code)
  • legacy systems need to keep code to keep data
  • huge IT infrastructures
  • hello world program is very complex
  • Model before Data (you need to know what you
    want)
  • poor time to market, high cost
  • SQL Objects are not enough
  • middleware, data marshalling,
  • No querying of objects, no encapsulation in SQL
  • teure (five star guru) programmers needed
  • XML Decouple Data and Schema!!!

20
Killer XML advantages
  • Code/schema/data independence
  • Covers the continuous spectrum from totally
    structured data to documents
  • from data management to information management
  • Unique model for representing data, metadata and
    code

21
Data metadata code
  • Data (XML), schemas (XML Schemas) and code (XSLT,
    XQuery) they all have an XML syntax
  • Easy to mix and match
  • Data in the schemas (not yet)
  • Data in code (already done)
  • Code in schemas (not yet)
  • Code in the data (not yet) dynamic data

22
Misunderstanding about XML
  • Data is self-describing.
  • Tags dont hold semantics, they only hold the
    structure of the information
  • The interpretation of the tags is in the
    application that handles the data, not in the
    tags themselves.

23
XML handicaps
  • Tree, and not a graph.
  • Many limitations derive from here, and many
    complications in the XML processing languages.
  • Difficulty in modeling NM relationships
  • The notion of reference (e.g. XLink, XPointer)
    not well integrated in the XML stack
  • Duplication of concepts
  • Many ways to do the same thing
  • Justification for a simpler data model like RDF
  • Concepts that seem logically unnecessary
  • PIs, comments, documents, etc
  • Additional complexity factors
  • xsinil, QName in content, etc
  • Not a complete application server (dev, depl.,
    mang.)

24
Advantages and disadvantages
  • 1. Handles the dual aspect of information
    lexical and binary 1 and 01
  • Essential feature for the 21st century
    information management
  • E.g. XML-based contract to be used in a legal
    procedure
  • Lots of complexity derives from here
  • XML Schema deals with both lexical and binary
    constraints
  • XML Data Model has to include both the
    dmtyped-value and dmstring-value
  • Processing language like XQuery and XSLT have to
    define their semantics for both aspects
  • XML data storage and indexing heavily impacted

25
Advantages and disadvantages
  • 2. Data is context sensitive.
  • We cannot do cut and paste in XML
  • Certain aspects of the data depend on the context
    where the fragment of data occurs (base-URIs,
    namespaces,etc)
  • Valuable feature for document management
  • Very hard consequences on storing, indexing and
    processing XML
  • Semantics of expressions also depends on the
    context where they appear
  • Additional consequences on expression evaluation

26
Sources of XML data ?
  • Inter-application communication data (WS, Rest,
    etc)
  • Mobile devices communication data
  • Logs
  • Blogs (RSS)
  • Metadata (e.g. Schema, WSDL, XMP)
  • Presentation data (e.g. XHTML)
  • Documents (e.g. Word)
  • Views of other sources of data
  • Relational, LDAP, CSV, Excel, etc.
  • Sensor data
  • It would be interesting to know the pie-chart
    and the evolution of each branch !

27
Some vertical application domains for XML
  • HealthCare Level Seven http//www.hl7.org/
  • Geography Markup Language (GML)
  • Systems Biology Markup Language (SBML)
    http//sbml.org/
  • XBRL, the XML based Business Reporting standard
    http//www.xbrl.org/
  • Global Justice XML Data Model (GJXDM)
    http//it.ojp.gov/jxdm
  • ebXML http//www.ebxml.org/
  • e.g. Encoded Archival Description Application
    http//lcweb.loc.gov/ead/
  • Digital photography metadata XMP
  • An XML grammar for sensor data (SensorML)
  • Real Simple Syndication (RSS 2.0)
  • Basically everywhere.

28
RosettaNet
  • http//www.rosettanet.org
  • Non-profit Organisation
  • Sponsors IBM, Oracle, NEC, ...
  • More than 400 additional members
  • Goals
  • Dynamic, flexible trading networks
  • Operational efficiency (cost reduction)
  • New business opportunities
  • Technical Goals
  • Common language, standard processesfor sharing
    of electronic business information

29
RosettaNet
  • PIPs Partner Interface Processes
  • 8 Clusters
  • Support
  • Partner Product and Service Review
  • Product Information
  • Order Management
  • Inventory Management
  • Marketing Information Management
  • Service and Support
  • Manufacturing
  • Segments wiht PIP Definitions in each Cluster

30
3 Order Management
  • Segment 3a Quote and Order Entry
  • Segment 3b Transportation and Distribution
  • Segment 3c Returns and Finance
  • Segment 3d Product Configuration

31
Quote and Order Entry
32
Example DTD
lt!-- RosettaNet XML Message Schema
3A1_MS_R02_00_QuoteRequest.dtd (16-Apr-2001
1246) This document has been prepared by
Edifecs (http//www.edifecs.com/) based On
the Business Collaboration Framework from
requirements in conformance with the
RosettaNet methodology. --gt lt!ENTITY
common-attributes "id CDATA IMPLIED" gt
lt!ELEMENT Pip3A1QuoteRequest (
fromRole , GlobalDocumentFunctionCode
, Quote , thisDocumentGenerati
onDateTime , thisDocumentIdentifier ,
toRole ) gt
33
Example DTD (ctd.)
lt!ELEMENT fromRole (
PartnerRoleDescription ) gt lt!ELEMENT
PartnerRoleDescription (
ContactInformation? ,
GlobalPartnerRoleClassificationCode ,
PartnerDescription ) gt lt!ELEMENT
ContactInformation ( contactName ,
EmailAddress , facsimileNumber?
, telephoneNumber ) gt lt!ELEMENT
contactName ( FreeFormText ) gt
lt!ELEMENT FreeFormText ( PCDATA )
gt lt!ATTLIST FreeFormText xmllang
CDATA IMPLIED gt
34
Example DTD (ctd.)
lt!ELEMENT Quote ( comments? ,
financedBy? , GlobalGovernmentPriorityR
atingCode? , GlobalQuoteTypeCode ,
governmentContractIdentifier? ,
PriceCondition? , QuoteCustomerInformati
on? , QuoteLineItem ,
quoteRequestIdentifier ,
requestedResponseDate? ,
RequoteReference? , respondTo ,
submittedDate? , TaxExemptStatus? ,
transportedBy? ) gt
35
ebXML
  • http//www.ebxml.org
  • OASIS Organization for the Advancement of
    Structured Information Standards
  • Non profit, ... (like RosettaNet)
  • Competition to RosettaNet
  • ebXML Mission To provide an open XML based
    infrastructure enabling the global use of
    electronic business information in an
    interoperable, secure and consistent manner for
    all parties.
  • Uses XML Schema (not DTDs)

36
ebXML Example (SOAP)
ltSOAPEnvelope xmlnsSOAP"http//schemas.xmlsoap.
org/ xmlnsxsi"http//www.w3.org/2001/XMLSche
ma-instance" xsischemaLocation"http//schemas.
xmlsoap.org/gt ltSOAPHeader
xmlnseb"http//www.oasis-open.org/
xsischemaLocation"http//gt
ltebMessageHeader ...gt
... lt/ebMessageHeadergt lt/SOAPHeadergt ltSOAPBo
dy xmlnseb"http//www.oasis-open.org/
xsischemaLocation"http//gt ltebManifest
ebversion"2.0"gt ... lt/ebManifestgt lt/SOA
PBodygt lt/SOAPEnvelopegt
37
ebXML Header Info (u.a.)
  • Conversation ID
  • ltebConversationIDgt2000-33-15-7lt/ebConversationID
    gt
  • Sender and Recipient
  • ltebFromgt
  • ltebPartyId ebtype urndunsgt123lt/ebPartyI
    dgt
  • ltebPartyId ebtype SCACgtRDWYlt/ebPartyIdgt
  • ltebRolegthttp//rosettanet.org/roles/Buyerlt/eb
    Rolegt
  • lt/ebFromgt
  • ltebTogt
  • ltebPartIdgtmailtojoe_at_example.comlt/ebPartIdgt
  • ltebRolegthttp//rosettanet.org/roles/Sellerlt/eb
    Rolegt
  • lt/ebTogt
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