A VERY brief History of Databases

1
A VERY brief History of Databases

• Calculators
• Structured databases (numbers)
• Full text databases (words)
• Tricks to combine Structure and text

2
Today

• Two worlds merge
• Business (numbers)
• Publishing (words)
• Common standards (Internet)
• TCP/IP
• HTTP
• XML

3
What is XML?

• eXtensible Markup Language
• A language to publish and facilitate exchange of
  data on the web
• W3C Recommendation
• February 1998

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Zoom in on XML

• A Metalanguage
• A language that defines rules on how to markup
  (tag) documents
• Use to pre-define a set of markup tags
• Use to pre-define rules for using these tags
• Documents tagged according to a model Instances

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XMLove at first sight

• ltLettergt
• ltTogtLeonidlt/Togt
• ltFromgtJameslt/Fromgt
• ltSubjectgtMeeting in St P. lt/Subjectgt
• ltContentgtI will come to the meetinglt/Contentgt
• lt/Lettergt

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The same in HTML

• ltBodygt
• ltH1gtTo Leonidlt/H1gt
• ltH2gtFrom Jameslt/H2gt
• ltH2gtSubject Meeting in St P. lt/H2gt
• ltPgtI will come to the meeting
• lt/Bodygt

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Differences

• HTML
• Fixed set of tags
• H1, H2, p, table, div
• Structure , Content and  look   mixed together
• Character problems

• XML
• Unlimited user-defined tags
• Structure, Content and  look  separate
• All characters in one instance

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Content

• The information
• Text, graphic, sound
• Produced by the author
• Reusable

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Look

• Helps the reader
• Bold titles, italics etc. help to give structure
  to the content
• But if you want a different look you need to
  re-work the content

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Structure

• Organise the content
• Set rules
• Hierarchy
• Links
• Blocs of information

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But also

• Meta-Data
• Identify the document
• Index,
• Classify
• Archive
• Re-use

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The building blocks

• Structure
• Tags
• (Well Formed)
• DTD
• (Valid)

Content XML editor gt XML document
Look CSS XSL
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In Practice

• An XML Letter DTD
• An XML Letter instance
• An  XML   Letter Style Sheet

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A Letter DTD
lt!ELEMENT Letter (PCDATA Sender Content
Recipient )gtlt!ELEMENT Sender (PCDATA Name
Address )gtlt!ELEMENT Name (PCDATA FirstName
LastName )gtlt!ELEMENT FirstName (PCDATA
)gtlt!ELEMENT StreetNumber (PCDATA )gtlt!ELEMENT
StreetName ANYgtlt!ELEMENT City (PCDATA
)gtlt!ELEMENT PostCode ANYgtlt!ELEMENT Country
(PCDATA )gtlt!ELEMENT Recipient (PCDATA Name
Address )gtlt!ELEMENT Content (PCDATA Para
)gtlt!ELEMENT Para (PCDATA )gtlt!ELEMENT Address
(PCDATA StreetNumber StreetName PostCode
City Country )gtlt!ELEMENT LastName (PCDATA
)gt
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A Letter XML Instance

• lt?xml version"1.0"?gt
• lt?xml-stylesheet href"../../../../../Program20Fi
  les/SoftQuad/XMetaL20220Eval/display/Letter.css"
  type"text/css"?gt
• lt!DOCTYPE Letter SYSTEM "Letter.dtd"gt
• ltLettergtltSendergt
• ltNamegtltFirstNamegtJameslt/FirstNamegtltLastNamegt
• Lawsonlt/LastNamegtlt/NamegtltAddressgtltStreetNumbergt1
• lt/StreetNumbergtltStreetNumbergtRue
  Boecklinlt/StreetNumbergt
• ltPostCodegt67075lt/PostCodegt
• ltCitygtSrasbourglt/CitygtltCountrygtFrancelt/Countrygtlt/A
  ddressgtlt/SendergtltContentgtDear
• Leonid,ltParagtThank you for your invitation to the
  24th European Meeting. I look
• forward to meeting you and other members of the
  human rights community to
• discuss issues related to human rights
  information handling.lt/ParagtltParagtI am
• sorry I did not send details of my passport
  earlierlt/ParagtltParagtYours
• sincerely,lt/Paragtlt/ContentgtltRecipientgt
• ltNamegtltFirstNamegtLeonidlt/FirstNamegtltLastNamegt
  Lvovlt/LastNamegtlt/NamegtltAddressgt
• ltCitygtSt Petersbourglt/Citygtlt/Addressgtlt/Recipientgtlt
  /Lettergt

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A Letter Style Sheet

• / Use Times New Roman for default font /
• DOCUMENT
• font-family "Times New Roman"
• font-size 12pt
• margin-top 5px
• margin-left 5px
• COMMENT
• display block
• color purple
• white-space pre
• PROCINS
• color black
• background-color c0c0c0

Sender text-align right font-family
"Andale Mono" font-weight bold font-size
10pt displayblock Letter text-align
left font-family "Andale Mono" font-style
normal font-weight normal font-size
10pt displayblock Address b text-align
inherit font-weight bold font-family
"Andale Mono" Para displayblock text-alignl
eft margin-top10
Name white-spacenormal text-aligninherit disp
layblock LastName white-spacenormal text-al
igninherit PostCode displayblock text-align
right City text-aligninherit displayblock
FirstName text-aligninherit
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The end result
Letter
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In a Human Rights Context

• An example

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In a HURIDOCS Context

• WINEVSYS

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In a HURIDOCS Context

• XMLEVSYS

lt!DOCTYPE Person SYSTEM  Person.dtd"gtltPersongt ltI
dgt1lt/IdgtltNamegtLawson, Jameslt/NamegtltSexgt01lt/Sexgt
lt Dependentsgt2lt/DependentsgtltOccupationgt0103lt/Occu
pationgt lt/Persongt
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What are the Benefits?

• Data gains independance
• From software
• From publishing medium
• Data can be re-used
• Extracted from an XML instance
• Processed
• Reformatted

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XML Confusion

• Your tag is not my tag
• ltBookgt
• ltTitlegtHuman rights in Europelt/Titlegt
• lt/Bookgt
• is not
• ltAddressgt
• ltTitlegtPresidentlt/Titlegt
• ltNamegtKabilalt/Namegt
• lt/Addressgt

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XML NAMESPACE

• Remove ambiguity
• Why not
• xmlnsHR"http//www.huridocs.org./Events"

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The tools

• XML Editor
• Notepad, XMETAL, Word i4i, WordPerfect
• or
• XML browsers
• IE5, (Netscape 6)
• Or
• XML Databases

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Information sources

• www.w3.org
• www.oasis-open.org
• www.w3schools.com/xml
• www.xml.org
• www.legalxml.org