XML An Overview

1
XMLAn Overview
XBRL Workshop, August 2006

• Roger DebrecenyUniversity of Hawaii
• Skip WhiteUniversity of Delaware

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XMLThe eXtensible Markup Language
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Markup languages

• What is a markup language?
• Markup languages markup text (data) so that one
  string of text can be distinguished from another!
• What does the following mean?
• 141 68 7.5

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XML

• Markup language
• Could be anything space, comma, tab ,
• Need agreement on the markup!
• eXtensible
• Able to extend
• Need agreement on the markup rules!
• ltweightgt 141 lt/weightgt
• ltheightgt 68 lt/heightgt
• ltshoeSizegt 7.5 lt/shoeSizegt

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HTML

• HyperText Markup Language
• An agreed-on language for creating Web pages
• A fixed set of tags as markup
• ltheadgt
• lttitlegt My Web Page lt/titlegt
• lt/headgt
• ltbodygt
• ltcentergt Hello Welcome to my Web page!
  lt/centergt
• lt/bodygt
• Tells a browser how to display things!

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XML - markup for documents

• The markup rules syntax that all well-formed
  XML documents must follow
• One and only one root element
• All elements must be properly nested
• All non-empty elements must have the same
  beginning and ending tag names (case-sensitive)
• Elements can contain data items or other elements
  (mixed is considered bad form)
• All elements can contain attributes

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XML Elements

• The basic unit of all XML documents is the
  element
• A root element
• Is the master element the overall container
• Its name tells what the document is all about
• Simple elements contain data values and do not
  have attributes
• ltIdNumbergt 12345 lt/IdNumbergt
• Complex elements have attributes and/or other
  elements nested within
• ltWeight unitsOZSgt12.00lt/Weightgt
• ltInventoryItemgt
• ltIdNumbergt12345lt/IdNumbergt
• ltWeight unitsOZSgt12.00lt/Weightgt
• lt/InventoryItemgt

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XML document (part 1)

• ltSalesOrdergt
• ltCustomerInformationgt
• ltCustomerNumbergt12345lt/CustomerNumbergt
• ltAddress typeshipping sameAsbillinggt
• ltFirstNamegtSkiplt/FirstNamegt
• ltLastNamegtWhitelt/LastNamegt
• ltStreetAddress1gt 1234 Main Street
  lt/StreetAddress1gt
• ltStreetAddress2gtlt/StreetAddress2gt
• ltCitygt Newark lt/Citygt
• ltStategt DE lt/Stategt
• ltZipCodegt 19716 lt/ZipCodegt
• ltCountrygt USA lt/Countrygt
• lt/Addressgt
• ltAddress typebilling sameAsshipping/gt
• lt/CustomerInformationgt

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XML document (part 2)

• ltOrderInformationgt
• ltOrderNumbergt111lt/OrderNumbergt
• ltOrderDategt2006-08-02lt/OrderDategt
• ltCreditCard type"VISA"gt
• ltCardHolderNamegt Skip Whitelt/CardHolderNamegt
  
• ltCardNumbergt 1234567891011213lt/CardNumbergt
• ltExpirationDategt 2009-05lt/ExpirationDategt
• lt/CreditCardgt
• ltItemgt
• ltItemIdgtsrh123lt/ItemIdgt
• ltItemDescriptiongt Specialized RH Mountain
  Bike
• lt/ItemDescriptiongt
• ltSize units"in"gt19lt/Sizegt
• ltQuantityOrderedgt 1lt/QuantityOrderedgt
• ltSalePrice units"USD"gt
  550.00lt/SalePricegt
• lt/Itemgt
• lt/OrderInformationgt

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XML documents

• What can we say about XML documents?
• XML documents are made up of tags (markup) that
  add meaning/context to data items
• A pair or tags and its content is known as an
  element
• XML elements can contain attributes within the
  beginning tag attributes add meaning!
• The XML attribute format is attributeNamevalue
  
• XML documents are structured in a strict
  hierarchy
• Well-formed XML documents can be processed by an
  XML processor

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XML Documents

• Why are XML documents so popular for storing and
  transforming information on networks?
• Easy to create understand
• Contain data with meaning context
• Processing data as information
• Very efficient for computers to process
• A standardized and non-proprietary language

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XML Fundamentals

• XML documents are hierarchical
• Structured as tree-like hierarchies
• XML documents are self-describing
• Each piece of data (information) has descriptive
  information associated with it
• XML is directly usable over the Internet
• Designed for storing delivering information
• XML does not currently replace HTML
• XML describes the content while in most cases
  HTML is used to tell a browser how to display it

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Information in XML Documents

• So What do you have when you have information
  in XML documents?
• You have information that can be understood by
  humans as well as ANY COMPUTER APPLICATION!!!
• XML is being referred to as the Rosetta Stone of
  networked computing!
• The transfer of information between computer
  applications and between computers and humans
  will become much more intelligible and automatic

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XML specifications

• XML is a set of rules and syntax for creating XML
  documents and specifications (stds.) that extend
  the capabilities of XML
• XML documents are used to store and transfer
  structured data over computer networks
• XML specifications extend the basic rules of XML
  to create languages vocabularies to be used to
• Define the contents structure of XML documents
• Process XML documents
• Create languages to support XML document
  processing

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XML Specifications

• XML Schema language
• To define the allowable contents structure of
  XML documents to create additional XML specs.
• XML Namespaces (xmlns)
• A collection of element names attributes for a
  particular purpose - like business reporting
  they help to avoid naming collisions!
• XML Linking Language (XLink)
• Attributes to be used to define sophisticated
  links between networked resources
• XBRL a special purpose XML vocabulary!

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XML namespaces

• The naming collision problem
• What if within your company, you have an
  accounting department a shipping department and
  they each want to use the XML element name
  status to mean things uniquely relevant to
  them?
• In accounting, status is used to mean billed or
  not!
• In shipping, status is used to mean shipped or
  not!

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XML namespaces

• The solution
• Create a separate namespace for each department
  within each namespace, define the element name
  status
• myCompany.com/xml/accounting
• Preferred namespace prefix acct
• ltstatusgt billed (notBilled) lt/statusgt
• myCompany.com/xml/shipping
• Preferred namespace prefix ship
• ltstatusgt shipped (notShipped) lt/statusgt

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XML namespaces in XML docs.(a sales order status
report)

• ltSalesOrderStatus
• xmlnsaccthttp//myCompany.com/xml/accounti
  ng
• xmlnsshiphttp//myCompany.com/xml/shipping
  gt
• ltOrderNumbergt 12345 lt/OrderNumbergt
• ltOrderDategt 2006-08-02lt/OrderDategt
• ltshipStatusgt shipped lt/shipStatusgt
• ltacctStatusgt notBilled lt/acctStatusgt
• lt/SalesOrderStatusgt

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XML Namespaces

• XML namespaces
• Contain a collection of elements attributes for
  a particular purpose
• In XML documents
• Namespaces must be declared using the xmlns
  attribute (usually declared in the root element)
• xmlnsprefixhttp namespace URI
• After declaration, a namespace prefix can be
  appended to an element or an attribute
  designates that it was defined in a particular
  namespace (for a particular purpose)
• ltus-gaap-ciCurrentAssetsgt10000lt/us-gaap-ciCurren
  tAssetsgt

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XLink language

• The XML XLink language
• A link is an explicit relationship between any
  addressable resources information or services
• The XLink specification defines a set of
  attributes that can be used with any XML element
  to create explicit relationships
• Simple links (commonly seen on Web pages) are
  unidirectional from a source to a target doc.
• Extended links are two-way and multidirectional
  and can describe relationships

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Xlink language

• XLink is used heavily in the XBRL specification
  ( in XBRL documents)
• To link a taxonomy to an XBRL instance document
• ltlinkschemaRef xlinktypesimple
  xlinkhrefus-gaap-ci-2005-02-28.xsd/gt
• ltus-gaap-ciCurrentAssetsgt10000lt/us-gaap-ciCurren
  tAssetsgt
• To define relationships between facts reported in
  an XBRL instance document
• To create linkbases to provide additional
  information about accounting concepts in instance
  documents

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Summary Introduction to XML

• XML is a set of rules and syntax for creating XML
  documents and specifications (stds.) that extend
  the capabilities of XML
• XML documents are used to hold and transfer
  structured data over computer networks
• XML specifications extend the basic rules of XML
  to create languages vocabularies
• XML Namespaces
• XML XLink language
• XML Schema language
• XBRL a special purpose XML vocabulary

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Reference material

• W3C Schools XML tutorial http//www.w3schools.c
  om/xml/default.asp
• W3C Schools HTML tutorial http//www.w3schools.
  com/html/default.asp
• HTMLHelp.com HTML references tutorials
  http//www.htmlhelp.com/