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XML

XML. Extensible Markup Language. XML. Metalanguage A Language, which describes languages Languages describe formats for data exchange. Example. Hans Meyer Lohmannstrasse 23 06366 Köthen Dr. Else Müller Bernburger Strasse 56 06366 Köthen. <Patient> <Name> <Strasse> <Ort>

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XML

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  1. XML Extensible Markup Language

  2. XML • Metalanguage • A Language, which describes languages • Languages describe formats for data exchange

  3. Example Hans Meyer Lohmannstrasse 23 06366 Köthen Dr. Else Müller Bernburger Strasse 56 06366 Köthen

  4. <Patient> <Name> <Strasse> <Ort> </Patient> <Arzt> <Name> <Strasse> <Ort> </Arzt> </Name> </Strasse> </Ort> </Name> </Strasse> </Ort> Hans Meyer Lohmannstrasse 23 06366 Köthen Dr. Else Müller Bernburger Strasse 56 06366 Köthen Example

  5. Structure of XML documents • Prolog • Deklaration of type of dokument • DTD (Document Type Definition) • Elements http://www.w3schools.com/xml/default.asp http://de.selfhtml.org/

  6. Document Type DefinitionDTD • It describes the grammar of a XML - document • It describes permitted elements and attributes • their data type and range of values • their nesting • An XML – Dokument, that conforms to a DTD is called valid

  7. Example DTD <?xml version="1.0" encoding="ISO-8859-1"?> <!DOCTYPE Personen [ <!ELEMENT Personen (Patient)> <!ELEMENT Patient (#PCDATA)> ]> <Personen> <Patient> Hans Meyer Lohmannstrasse 23 06366 Köthen </Patient> </Personen> http://www.inf.hs-anhalt.de/~Worzyk/Telemedizin/Beispiele/Patienten1.xml

  8. Structure of XML documents • DTD describes the characteristics of the elements • Elements are initiated by a start tag <Elementname> and are terminated by a closing tag </Elementname>. • XML tags are case sensitive • Elements can contain Elements. • #PCDATA Parsed character data: The elements consist of character strings whose characters are part of the defined character set.

  9. Names of Elements • Names can contain letters, numbers, and other characters • Names must not start with a number or punctuation character • Names must not start with the letters xml (or XML or Xml ..) • Names cannot contain spaces

  10. Sequence of Elements Subordinate elements are separated in the declaration by commas and included in parentheses. Example: <?xml version="1.0" encoding="ISO-8859-1"?> <!DOCTYPE Personen [ <!ELEMENT Personen (Patient,Arzt)> <!ELEMENT Patient (Name,Adresse)> <!ELEMENT Arzt (Name, Adresse)> <!ELEMENT Name (#PCDATA)> <!ELEMENT Adresse (#PCDATA)> ]> http://www.inf.hs-anhalt.de/~Worzyk/Telemedizin/Beispiele/Patienten2.xml http://www.inf.hs-anhalt.de/~Worzyk/Telemedizin/Beispiele/Patienten3.xml

  11. selection list • Selection of exactly one element: The available elements are seperated by | • Example: <!DOCTYPE Personen [ <!ELEMENT Personen (Patient|Arzt)> <!ELEMENT Patient (Name,Adresse,Diagnose)> <!ELEMENT Arzt (Name, Adresse,Fachgebiet)> http://www.inf.hs-anhalt.de/~Worzyk/Telemedizin/Beispiele/Patienten4.xml

  12. Multiple occurrence * The element can appear no time or arbitrarily often + The element can appear at least one time or arbitrarily often ? The element can appear no time or at most one time

  13. Worzyk FH Anhalt Attributes <!ATTLIST element-name attribute-name attribute-type default-value> Types of attriutes:: CDATA, (en1|en2|..), ID, IDREF, IDREFS, NMTOKEN, NMTOKENS, ENTITY, ENTITIES, NOTATION, xml: Defaultvalue: value #REQUIRED, #IMPLIED, #FIXED value http://www.inf.hs-anhalt.de/~Worzyk/Telemedizin/Beispiele/Patienten5.xml http://www.w3schools.com/xml/xml_attributes.asp Datenbanksysteme 2 SS 2004 Seite 13 - 13

  14. Comments Comments are embedded by <!– and --> <!-- This is a comment -->

  15. Well-formed XML - File • The file starts with the XML-declaration, which establish the reference to XML • It exists at least one data element • It exists exactly one root element, which contain all other data elements • All required attributes are defined • All elements have the right content • The elements must be nested properly

  16. Valide XML - File • The file is well-formed • A DTD is assigned to the file • The content of the file is according to the assigned DTD

  17. Parser A parser validates if an XML Document is valide: <html> <body> <script type="text/javascript"> var xmlDoc = new ActiveXObject("Microsoft.XMLDOM") xmlDoc.async="false" xmlDoc.validateOnParse="true" xmlDoc.load("Patienten5.xml") document.write("<br />Error Code: ") document.write(xmlDoc.parseError.errorCode) document.write("<br />Error Reason: ") document.write(xmlDoc.parseError.reason) document.write("<br />Error Line: ") document.write(xmlDoc.parseError.line) </script> </body> </html> http://www.inf.hs-anhalt.de/~Worzyk/Telemedizin/Beispiele/Parser.htm

  18. DTD - Disadvantages • Few datatypes • specification not in XML – Syntax • Specification can not be validated with a parser

  19. XML - Schema • An XML Schema: • defines elements that can appear in a document • defines attributes that can appear in a document • defines which elements are child elements • defines the order of child elements • defines the number of child elements • defines whether an element is empty or can include text • defines data types for elements and attributes • defines default and fixed values for elements and attributes http://www.w3schools.com/schema/schema_intro.asp

  20. XML SchemaAdvantages over DTD • XML Schemas are extensible to future additions • XML Schemas are richer and more useful than DTDs • XML Schemas are written in XML • XML Schemas support data types • xs;date, xs;dateTime, xs:string • XML Schemas support namespaces • xmlns:xs="http://www.w3.org/2001/XMLSchema“

  21. Dublin Core Standard Dublin Core Metadata Initiative Conference in 1995 in Dublin / Ohio defined a set of describing attributs to categorize documents in the internet 15 core elements are recommended in „Dublin Core Metadata Element Set, Version 1.1 (ISO 15836)“ http://dublincore.org/documents/dces/

  22. How to create an XML structure • Create a tree-structure of the data • Convert that structure to a DTD • Add data elements • Test

  23. ExampleQuarterly billing • One file consists of exactly one physician and at least one patient • A phyiscian is either a General Practitioner or a dentist • A general practitioner has an address and a profession • A dentist has an address • A patient has an address and no ore more diagnisis • An address consists of Name, City, Street • A name has a salutation Mr. or Ms.

  24. ExampleQuarterly billing billing + Physician Patient | * General Practitioner Dentist Address Diagnosis Profession ? Address Adresse Name City Street Mr Ms

  25. Example - DTD <?xml version="1.0" encoding="ISO-8859-1"?> <!DOCTYPE Billing [ <!ELEMENT Billing (Physician, Patient+)> <!ELEMENT Physician (General_Practitioner | Dentist)> <!ELEMENT General_Practitioner (Address, Profession?)> <!ELEMENT Dentist (Address)> <!ELEMENT Patient (Address, Diagnosis*)> <!ELEMENT Address (Name, City, Street)> <!ELEMENT Profession (#PCDATA)> <!ELEMENT Diagnosis (#PCDATA)> <!ELEMENT Name (#PCDATA)> <!ELEMENT City (#PCDATA)> <!ELEMENT Street (#PCDATA)> <!ATTLIST Name Salutation (Mr|Ms) "Ms"> ]>

  26. Example - Data < Billing > < Physician > < General_Practitioner > <Address> <Name>Dr. Erpel</Name> <City>Entenhausen</City> <Street>Am Krankenhaus 1</Street> </Address> < Profession >Geriatrics</ Profession > </ General_Practitioner > </ Physician > < Patient > <Address> <Name Anrede="Herr">Daniel</Name> <City>Entenhausen</City> <Street>Bahnhofstrasse 3a</Street> </Address> <Diagnose>Bettflucht</Diagnose> </Patient> <Patient> <Address> <Name>Daisy</Name> <City>Entenhausen</City> <Street>Am Stadtpark</Street> </Address> <Diagnosis>Sonnenbrand</Diagnosis> <Diagnosis>Migräne</Diagnosis> </Patient> </ Billing >

  27. Queries to XML - Files • XPath • XQuery

  28. XPath The language XPath serves to address parts of a XML document. It was designed for the use both in XSLT and in XPointer. XPath models a XML document as a tree, which consists of knots. http://www.informatik.hu-berlin.de/~obecker/obqo/w3c-trans/xpath-de-20010702/

  29. Example <?xml version="1.0" encoding="ISO-8859-1"?><bookstore><book category="COOKING">  <title lang="en">Everyday Italian</title>  <author>Giada De Laurentiis</author>  <year>2005</year>  <price>30.00</price></book><book category="CHILDREN">  <title lang="en">Harry Potter</title>  <author>J K. Rowling</author>  <year>2005</year>  <price>29.99</price></book><book category="WEB">  <title lang="en">XQuery Kick Start</title>  <author>James McGovern</author>  <author>Per Bothner</author>  <author>Kurt Cagle</author>  <author>James Linn</author>  <author>Vaidyanathan Nagarajan</author>  <year>2003</year>  <price>49.99</price></book><book category="WEB">  <title lang="en">Learning XML</title>  <author>Erik T. Ray</author>  <year>2003</year>  <price>39.95</price></book></bookstore>

  30. Queries with XPath Select all titles: /bookstore/book/title Select the title of the first book /bookstore/book[1]/title Select all the prices /bookstore/book/price/text() Select price nodes with price>35 /bookstore/book[price>35]/title http://www.w3schools.com/xpath/xpath_examples.asp

  31. XQuery • Querylanguage for XML data • Uses Xpath expression • Analogy to SQL

  32. Xquery Example <?xml version="1.0" encoding="ISO-8859-1"?> <bib> <book year="1994"> <title>TCP/IP Illustrated</title> <author><last>Stevens</last><first>W.</first></author> <publisher>Addison-Wesley</publisher> <price>65.95</price> </book> <book year="1992"> <title>Advanced Programming in the Unix environment</title> <author><last>Stevens</last><first>W.</first></author> <publisher>Addison-Wesley</publisher> <price>65.95</price> </book> <book year="2000"> <title>Data on the Web</title> <author><last>Abiteboul</last><first>Serge</first></author> <author><last>Buneman</last><first>Peter</first></author> <author><last>Suciu</last><first>Dan</first></author> <publisher>Morgan Kaufmann Publishers</publisher> <price>39.95</price> </book> <book year="1999"> <title>The Technology and Content for Digital TV</title> <editor> <last>Gerbarg</last><first>Darcy</first> <affiliation>CITI</affiliation> </editor> <publisher>Kluwer Academic Publishers</publisher> <price>129.95</price> </book> </bib>

  33. Xquery Example Query: doc("books.xml")/bib/book[price<50] results: <book year="2000"> <title>Data on the Web</title> <author><last>Abiteboul</last><first>Serge</first></author> <author><last>Buneman</last><first>Peter</first></author> <author><last>Suciu</last><first>Dan</first></author> <publisher>Morgan Kaufmann Publishers</publisher> <price>39.95</price> </book>

  34. FLWOR For, Let, Where, Order by, Return for $x in doc("books.xml")/bib/book where $x/price>50 order by $x/title return $x/title Results: <title>Advanced Programming in the Unix environment</title> <title>TCP/IP Illustrated</title> <title>The Technology and Content for Digital TV</title>

  35. XML – Documents in Databases XML – Documents can be • Focussed on data • Focussed on text • Semi-structured

  36. Alternatives to store XML Documents • Storage as a whole • Storage within the XML-Structure • Transformation to structures of the database

  37. Storage of XML documents as a whole Original will be stored in a file system or as CLOB in a database full-text index Strukturindex

  38. Example <hotel url=“http://www.hotel-huebner.de“ id=“h0001“ erstellt-am=“03/02/2003“ Autor=“Hans Müller“> <hotelname>Hotel Hübner</hotelname> <kategorie>4</kategorie> <adresse> <plz>18199</plz> <ort>Warnemünde</ort> <strasse>Seestraße</strasse> </adresse> <telefon>0381 / 5434-0</telefon> <fax> 0381 / 5434-444</fax> <anreisebeschreibung>Aus Richtung Rostock kommend ... </anreisebeschreibung> </hotel>

  39. full-text index <hotel url=“http://www.hotel-huebner.de“ id=“h0001“ erstellt-am=“03/02/2003“ Autor=“Hans Müller“> <hotelname>Hotel Hübner</hotelname> <kategorie>4</kategorie> <adresse> <plz>18199</plz> <ort>Warnemünde</ort> <strasse>Seestraße</strasse> </adresse> <telefon>0381 / 5434-0</telefon> <fax> 0381 / 5434-444</fax> <anreisebeschreibung>Aus Richtung Rostock kommend ... </anreisebeschreibung> </hotel>

  40. full-text - andStructurindex <hotel url=“http://www.hotel-huebner.de“ id=“h0001“ erstellt-am=“03/02/2003“ Autor=“Hans Müller“> <hotelname>Hotel Hübner</hotelname> <kategorie>4</kategorie> <adresse> <plz>18199</plz> <ort>Warnemünde</ort> <strasse>Seestraße</strasse> </adresse> <telefon>0381 / 5434-0</telefon> <fax> 0381 / 5434-444</fax> <anreisebeschreibung>Aus Richtung Rostock kommend ... </anreisebeschreibung> </hotel>

  41. Queries Volltextindex hotel AND warnemünde (hotel OR pension) AND (rostock OR warnemünde) Volletxt- und Strukturindex hotel.adresse.ort CONTAINS (“warnemünde“) AND hotel.freizeitmoeglichkeit CONTAINS (“swimming pool“)

  42. Characteristics full-text index

  43. generic storage Storage within the XML-Structure All Informationen of the XML-Dokument will be stored • simple generic Storage • Document Object Model

  44. Beispiel

  45. Document Object Model The structure of the tree will be transformed to a class hierarchy Storage in objectrelational or objektoriented databases

  46. Queries • XPath • QXuery • XQL • Abfragesprache der Software AG • SQL

  47. Characteristics Generic Storage

  48. Transformation to Structures of databases DTD or Schema must be available Automatic or userdriven procedures Transformtion to relational objectrelational objectoriented Databases

  49. Transformation

  50. Example

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