INF 523 Web Technologies with XML

1
INF 523 Web Technologies (with XML)

• Week 4
• Bahadir K. Akcam
• Fall 2006

2
Week 3

• Namespaces
• XML Schema (XSD)

3
XSD How To?

• lt?xml version"1.0"?gt
• ltnote xmlns"http//www.albany.edu"
  xmlnsxsi"http//www.w3.org/2001/XMLSchema-instan
  ce" xsischemaLocation"http//www.albany.edu
  note.xsd"gt
• lttogtTovelt/togt
• ltfromgtJanilt/fromgt
• ltheadinggtReminderlt/headinggt
• ltbodygtDon't forget me this weekend!lt/bodygt
• lt/notegt

4
XSD How To?

• An XML Schema called note.xsd
• lt?xml version"1.0"?gt
• ltxsschema xmlnsxs"http//www.w3.org/2001/XMLSch
  ema" targetNamespace"http//www.albany.edu"
  xmlns"http//www.albany.edu"
  elementFormDefault"qualified"gt
• ltxselement name"note"gt
• ltxscomplexTypegt
• ltxssequencegt
• ltxselement name"to" type"xsstring"/gt
• ltxselement name"from" type"xsstring"/gt
  ltxselement name"heading" type"xsstring"/gt
  
• ltxselement name"body" type"xsstring"/gt
• lt/xssequencegt
• lt/xscomplexTypegt
• lt/xselementgt
• lt/xsschemagt

5
Simple Element

• XML Schemas define the elements of your XML
  files.
• A simple element is an XML element that contains
  only text. It cannot contain any other elements
  or attributes.
• The text can be of many different types. It can
  be one of the types included in the XML Schema
  definition (boolean, string, date, etc.), or it
  can be a custom type that you can define
  yourself.
• You can also add restrictions (facets) to a data
  type in order to limit its content, or you can
  require the data to match a specific pattern.

6
Simple Element

• Syntax
• ltxselement name"xxx" type"yyy"/gt
• Built in data types
• xsstring
• xsdecimal
• xsinteger
• xsboolean
• xsdate
• xstime

7
Simple Element

• XML
• ltlastnamegtRefsneslt/lastnamegt
• ltagegt36lt/agegt
• ltdateborngt1970-03-27lt/dateborngt
• XSD
• ltxselement name"lastname" type"xsstring"/gt
• ltxselement name"age" type"xsinteger"/gt
• ltxselement name"dateborn" type"xsdate"/gt

8
Default and Fixed Values for Simple Elements

• Simple elements may have a default value OR a
  fixed value specified.
• A default value is automatically assigned to the
  element when no other value is specified.
• ltxselement name"color" type"xsstring"
  default"red"/gt
• A fixed value is also automatically assigned to
  the element, and you cannot specify another
  value.
• ltxselement name"color" type"xsstring"
  fixed"red"/gt

9
XSD Attributes

• All attributes are declared as simple types.
• Simple elements cannot have attributes. If an
  element has attributes, it is considered to be of
  a complex type. But the attribute itself is
  always declared as a simple type.
• Syntax
• ltxsattribute name"xxx" type"yyy"/gt
• ltlastname lang"EN"gtSmithlt/lastnamegt
• ltxsattribute name"lang" type"xsstring"/gt

10
XSD Attributes

• Default and Fixed Values for Attributes
• ltxsattribute name"lang" type"xsstring"
  default"EN"/gt
• ltxsattribute name"lang" type"xsstring"
  fixed"EN"/gt
• Optional and Required Attributes
• Attributes are optional by default. To specify
  that the attribute is required, use the "use"
  attribute
• ltxsattribute name"lang" type"xsstring"
  use"required"/gt

11
Restrictions on Content

• When an XML element or attribute has a data type
  defined, it puts restrictions on the element's or
  attribute's content.
• If an XML element is of type "xsdate" and
  contains a string like "Hello World", the element
  will not validate.
• With XML Schemas, you can also add your own
  restrictions to your XML elements and attributes.
  These restrictions are called facets. 

12
XSD Restrictions/Facets

• Restrictions are used to define acceptable values
  for XML elements or attributes. Restrictions on
  XML elements are called facets.

13
Restrictions on Values

• The following example defines an element called
  "age" with a restriction. The value of age cannot
  be lower than 0 or greater than 120
• ltxselement name"age"gt
• ltxssimpleTypegt
• ltxsrestriction base"xsinteger"gt
• ltxsminInclusive value"0"/gt
• ltxsmaxInclusive value"120"/gt
• lt/xsrestrictiongt
• lt/xssimpleTypegt
• lt/xselementgt

14
Restrictions on a Set of Values

• To limit the content of an XML element to a set
  of acceptable values, we would use the
  enumeration constraint.
• The example below defines an element called "car"
  with a restriction. The only acceptable values
  are Audi, Golf, BMW
• ltxselement name"car"gtltxssimpleTypegt
  ltxsrestriction base"xsstring"gt
  ltxsenumeration value"Audi"/gt
  ltxsenumeration value"Golf"/gt
  ltxsenumeration value"BMW"/gt
  lt/xsrestrictiongt lt/xssimpleTypegtlt/xselementgt
  

15
Restrictions on a Series of Values

• To limit the content of an XML element to define
  a series of numbers or letters that can be used,
  we would use the pattern constraint.

16
Restrictions on a Series of Values

• The example below defines an element called
  "letter" with a restriction. The only acceptable
  value is ONE of the LOWERCASE letters from a to
  z
• ltxselement name"letter"gt
• ltxssimpleTypegt
• ltxsrestriction base"xsstring"gt
• ltxspattern value"a-z"/gt
• lt/xsrestrictiongt
• lt/xssimpleTypegt
• lt/xselementgt

17
Restrictions on a Series of Values

• ltxselement name"initials"gt
• ltxssimpleTypegt
• ltxsrestriction base"xsstring"gt
• ltxspattern value"A-ZA-ZA-Z"/gt
• lt/xsrestrictiongt
• lt/xssimpleTypegt
• lt/xselementgt
• Defines an element called "initials" with a
  restriction. The only acceptable value is THREE
  of the UPPERCASE letters from a to z

18
Restrictions on a Series of Values

• ltxspattern value"a-zA-Za-zA-Za-zA-Z"/gt
• Defines an element called "initials" with a
  restriction. The only acceptable value is THREE
  of the LOWERCASE OR UPPERCASE letters from a to z
• ltxspattern value"xyz"/gt
• The only acceptable value is ONE of the following
  letters x, y, OR z

19
Restrictions on a Series of Values

• ltxspattern value"0-90-90-90-90-9"/gt
• The only acceptable value is FIVE digits in a
  sequence, and each digit must be in a range from
  0 to 9
• The acceptable value is zero or more occurrences
  of lowercase letters from a to z
• ltxspattern value"(a-z)"/gt

20
Restrictions on a Series of Values

• The acceptable value is one or more pairs of
  letters, each pair consisting of a lower case
  letter followed by an upper case letter. For
  example, "sToP" will be validated by this
  pattern, but not "Stop" or "STOP" or "stop"
• ltxspattern value"(a-zA-Z)"/gt
• ltxspattern value"malefemale"/gt
• The only acceptable value is male OR female

21
Restrictions on a Series of Values

• There must be exactly eight characters in a row
  and those characters must be lowercase or
  uppercase letters from a to z, or a number from 0
  to 9
• ltxspattern value"a-zA-Z0-98"/gt

22
Restrictions on Whitespace Characters

• To specify how whitespace characters should be
  handled, we would use the whiteSpace constraint.
• The whiteSpace constraint is set to "preserve",
  which means that the XML processor WILL NOT
  remove any white space characters
• ltxswhiteSpace value"preserve"/gt
• The whiteSpace constraint is set to "replace",
  which means that the XML processor WILL REPLACE
  all white space characters (line feeds, tabs,
  spaces, and carriage returns) with spaces
• ltxswhiteSpace value"replace"/gt
• The whiteSpace constraint is set to "collapse",
  which means that the XML processor WILL REMOVE
  all white space characters (line feeds, tabs,
  spaces, carriage returns are replaced with
  spaces, leading and trailing spaces are removed,
  and multiple spaces are reduced to a single
  space)
• ltxswhiteSpace value"collapse"/gt

23
Restrictions on Length

• To limit the length of a value in an element, we
  would use the length, maxLength, and minLength
  constraints.
• ltxselement name"password"gt
• ltxssimpleTypegt
• ltxsrestriction base"xsstring"gt
• ltxsminLength value"5"/gt
• ltxsmaxLength value"8"/gt
• lt/xsrestrictiongt
• lt/xssimpleTypegtlt/xselementgt
• ltxslength value"8"/gt
• Must be exactly eight characters

24
More Restrictions

• Restrictions for Datatypes
• Check end of the http//www.w3schools.com/schema/s
  chema_facets.asp

25
XSD Complex Elements

• A complex element contains other elements and/or
  attributes.
• There are four kinds of complex elements
• empty elements
• elements that contain only other elements
• elements that contain only text
• elements that contain both other elements and
  text

26
How to Define a Complex Element

• (1st way)
• ltemployeegt ltfirstnamegtJohnlt/firstnamegt
  ltlastnamegtSmithlt/lastnamegt lt/employeegt
• ltxselement name"employee"gt ltxscomplexTypegt
  ltxssequencegt ltxselement name"firstname"
  type"xsstring"/gt ltxselement name"lastname"
  type"xsstring"/gt lt/xssequencegt
  lt/xscomplexTypegt lt/xselementgt

27
How to Define a Complex Element

• (2nd way)
• ltxselement name"employee" type"personinfo"/gtlt
  xscomplexType name"personinfo"gt ltxssequencegt
  ltxselement name"firstname" type"xsstring"/gt
  ltxselement name"lastname" type"xsstring"/gt
  lt/xssequencegt lt/xscomplexTypegt

28
How to Define a Complex Element

• If you use the method described above, several
  elements can refer to the same complex type, like
  this
• ltxselement name"employee" type"personinfo"/gt
  ltxselement name"student" type"personinfo"/gt
  ltxselement name"member" type"personinfo"/gtltxs
  complexType name"personinfo"gt ltxssequencegt
  ltxselement name"firstname" type"xsstring"/gt
  ltxselement name"lastname" type"xsstring"/gt
  lt/xssequencegt lt/xscomplexTypegt

29
XSD Complex Empty Elements

• An empty complex element cannot have contents,
  only attributes.
• ltproduct prodid"1345" /gt
• 3 different ways
• ltxselement name"product"gt ltxscomplexTypegt
  ltxsattribute name"prodid" type"xsposi
  tiveInteger"/gt lt/xscomplexTypegt lt/xselementgt

30
XSD Complex Elements Text Only Elements

• A complex text-only element can contain text and
  attributes.
• This type contains only simple content (text and
  attributes), therefore we add a simpleContent
  element around the content.
• When using simple content, you must define an
  extension OR a restriction within the
  simpleContent element.

31
XSD Complex Elements Text Only Elements

• ltxselement name"somename"gt ltxscomplexTypegt
  ltxssimpleContentgt ltxsextension
  base"basetype"gt .... .... lt/xsextensiongt
  lt/xssimpleContentgt lt/xscomplexTypegt
  lt/xselementgt
• ltxselement name"somename"gt ltxscomplexTypegt
  ltxssimpleContentgt ltxsrestriction
  base"basetype"gt .... .... lt/xsrestrictiongt
  lt/xssimpleContentgt lt/xscomplexTypegt
  lt/xselementgt

32
Example

• ltshoesize country"france"gt35lt/shoesizegt
• ltxselement name"shoesize"gt ltxscomplexTypegt
  ltxssimpleContentgt ltxsextension
  base"xsinteger"gt ltxsattribute
  name"country" type"xsstring" /gt
  lt/xsextensiongt lt/xssimpleContentgt
  lt/xscomplexTypegt lt/xselementgt

33
XSD Complex Types With Mixed Content

• A mixed complex type element can contain
  attributes, elements, and text.
• ltlettergt Dear Mr.ltnamegtJohn Smithlt/namegt. Your
  order ltorderidgt1032lt/orderidgt will be shipped on
  ltshipdategt2001-07-13lt/shipdategt. lt/lettergt
• ltxselement name"letter"gt ltxscomplexType
  mixed"true"gt ltxssequencegt ltxselement
  name"name" type"xsstring"/gt ltxselement
  name"orderid" type"xspositiveInteger"/gt
  ltxselement name"shipdate" type"xsdate"/gt
  lt/xssequencegt lt/xscomplexTypegt lt/xselementgt

34
XSD Complex Types Indicators

• We can control HOW elements are to be used in
  documents with indicators.
• Indicators There are seven indicators
• Order indicators
• All
• Choice
• Sequence
• Occurrence indicators
• maxOccurs
• minOccurs
• Group indicators
• Group name
• attributeGroup name

35
Order Indicators

• Order indicators are used to define the order of
  the elements.
• All Indicator
• The ltallgt indicator specifies that the child
  elements can appear in any order, and that each
  child element must occur only once
• ltxselement name"person"gt ltxscomplexTypegt
  ltxsallgt ltxselement name"firstname"
  type"xsstring"/gt ltxselement name"lastname"
  type"xsstring"/gt lt/xsallgt lt/xscomplexTypegt
  lt/xselementgt

36
Choice Indicator

• The ltchoicegt indicator specifies that either one
  child element or another can occur
• ltxselement name"person"gt ltxscomplexTypegt
  ltxschoicegt ltxselement name"employee"
  type"employee"/gt ltxselement name"member"
  type"member"/gt lt/xschoicegt lt/xscomplexTypegt
  lt/xselementgt

37
Sequence Indicator

• The ltsequencegt indicator specifies that the child
  elements must appear in a specific order
• ltxselement name"person"gt ltxscomplexTypegt
  ltxssequencegt ltxselement name"firstname"
  type"xsstring"/gt ltxselement name"lastname"
  type"xsstring"/gt lt/xssequencegt
  lt/xscomplexTypegt lt/xselementgt

38
Occurrence Indicators

• Occurrence indicators are used to define how
  often an element can occur.
• For all "Order" and "Group" indicators (any, all,
  choice, sequence, group name, and group
  reference) the default value for maxOccurs and
  minOccurs is 1.
• maxOccurs Indicator
• The ltmaxOccursgt indicator specifies the maximum
  number of times an element can occur
• To allow an element to appear an unlimited number
  of times, use the maxOccurs"unbounded" statement
• minOccurs Indicator
• The ltminOccursgt indicator specifies the minimum
  number of times an element can occur

39
Example

• ltxselement name"person"gt ltxscomplexTypegt
  ltxssequencegt ltxselement name"full_name"
  type"xsstring"/gt ltxselement
  name"child_name" type"xsstring"
  maxOccurs"10" minOccurs"0"/gt
  lt/xssequencegt lt/xscomplexTypegt
  lt/xselementgt

40
Example XML File Myfamily.xml

• lt?xml version"1.0" encoding"ISO-8859-1"?gt
• ltpersons xmlnsxsi"http//www.w3.org/2001/XMLSche
  ma-instance" xsinoNamespaceSchemaLocation"family
  .xsd"gt
• ltpersongt
• ltfull_namegtHege Refsneslt/full_namegt
  ltchild_namegtCecilielt/child_namegt
• lt/persongt
• ltpersongt
• ltfull_namegtTove Refsneslt/full_namegt
  ltchild_namegtHegelt/child_namegt ltchild_namegtStalelt/c
  hild_namegt
• ltchild_namegtJimlt/child_namegt
• ltchild_namegtBorgelt/child_namegt
• lt/persongt
• ltpersongt
• ltfull_namegtStale Refsneslt/full_namegt
• lt/persongt
• lt/personsgt

41
Example XSD Schema family.xsd

• lt?xml version"1.0" encoding"ISO-8859-1"?gt
• ltxsschema xmlnsxs"http//www.w3.org/2001/XMLSch
  ema" elementFormDefault"qualified"gt
• ltxselement name"persons"gt
• ltxscomplexTypegt
• ltxssequencegt
• ltxselement name"person" maxOccurs"unbounded"gt
• ltxscomplexTypegt
• ltxssequencegt
• ltxselement name"full_name" type"xsstring"/gt
  
• ltxselement name"child_name" type"xsstring"
  minOccurs"0" maxOccurs"5"/gt
• lt/xssequencegt
• lt/xscomplexTypegt
• lt/xselementgt
• lt/xssequencegt
• lt/xscomplexTypegt
• lt/xselementgt
• lt/xsschemagt

42
Group Indicators

• Group indicators are used to define related sets
  of elements.
• Element Groups
• ltxsgroup name"groupname"gt ... lt/xsgroupgt
• You must define an all, choice, or sequence
  element inside the group declaration.

43
Group Indicators

• ltxsgroup name"persongroup"gt
• ltxssequencegt
• ltxselement name"firstname" type"xsstring"/gt
  
• ltxselement name"lastname" type"xsstring"/gt
• ltxselement name"birthday" type"xsdate"/gt
• lt/xssequencegt
• lt/xsgroupgt
• ltxselement name"person" type"personinfo"/gt
• ltxscomplexType name"personinfo"gt
• ltxssequencegt
• ltxsgroup ref"persongroup"/gt
• ltxselement name"country" type"xsstring"/gt
• lt/xssequencegt
• lt/xscomplexTypegt

44
Attribute Groups

• Attribute groups are defined with the
  attributeGroup declaration
• ltxsattributeGroup name"groupname"gt ...
  lt/xsattributeGroupgt

45
Attribute Groups

• ltxsattributeGroup name"personattrgroup"gt
  ltxsattribute name"firstname"
  type"xsstring"/gt ltxsattribute name"lastname"
  type"xsstring"/gt ltxsattribute name"birthday"
  type"xsdate"/gt
• lt/xsattributeGroupgt
• ltxselement name"person"gt ltxscomplexTypegt
  ltxsattributeGroup ref"personattrgroup"/gt
  lt/xscomplexTypegt
• lt/xselementgt

46
XSD The ltanygt Element

• The ltanygt element enables us to extend the XML
  document with elements not specified by the
  schema!
• By using the ltanygt element we can extend (after
  ltlastnamegt) the content of "person" with any
  element
• We have family.xsd, children.xsd, myfamily.xml
• family.xsd
• ltxselement name"person"gt ltxscomplexTypegt
  ltxssequencegt ltxselement name"firstname"
  type"xsstring"/gt ltxselement name"lastname"
  type"xsstring"/gt ltxsany minOccurs"0"/gt
  lt/xssequencegt lt/xscomplexTypegt lt/xselementgt

47
XSD The ltanygt Element

• Now we want to extend the "person" element with a
  "children" element.
• A new XSD document children.xsd
• lt?xml version"1.0" encoding"ISO-8859-1"?gt
  ltxsschema xmlnsxs"http//www.w3.org/2001/XMLSch
  ema" targetNamespace"http//www.w3schools.com"
  xmlns"http//www.w3schools.com"
  elementFormDefault"qualified"gtltxselement
  name"children"gt ltxscomplexTypegt
  ltxssequencegt ltxselement name"childname"
  type"xsstring" maxOccurs"unbounded"/gt
  lt/xssequencegt lt/xscomplexTypegt
  lt/xselementgtlt/xsschemagt

48
XSD The ltanygt Element

• Myfamily.xml
• lt?xml version"1.0" encoding"ISO-8859-1"?gtltperso
  ns xmlns"http//www.microsoft.com"
  xmlnsxsi"http//www.w3.org/2001/XMLSchema-instan
  ce" xsiSchemaLocation"http//www.microsoft.com
  family.xsd http//www.w3schools.com
  children.xsd"gtltpersongt ltfirstnamegtHegelt/firstna
  megt ltlastnamegtRefsneslt/lastnamegt ltchildrengt
  ltchildnamegtCecilielt/childnamegt lt/childrengt
  lt/persongtltpersongt ltfirstnamegtStalelt/firstnamegt
  ltlastnamegtRefsneslt/lastnamegt
  lt/persongtlt/personsgt

49
XSD The ltanyAttributegt Element

• The ltanyAttributegt element enables us to extend
  the XML document with attributes not specified by
  the schema.
• Works similar to ltAnygt element
• family.xsd
• ltxselement name"person"gt ltxscomplexTypegt
  ltxssequencegt ltxselement name"firstname"
  type"xsstring"/gt ltxselement name"lastname"
  type"xsstring"/gt lt/xssequencegt
  ltxsanyAttribute/gt lt/xscomplexTypegt
  lt/xselementgt

50
XSD The ltanyAttributegt Element

• We want to extend the "person" element with a
  "gender" attribute
• attribute.xsd
• lt?xml version"1.0" encoding"ISO-8859-1"?gt
  ltxsschema xmlnsxs"http//www.w3.org/2001/XMLSch
  ema" targetNamespace"http//www.w3schools.com"
  xmlns"http//www.w3schools.com"
  elementFormDefault"qualified"gtltxsattribute
  name"gender"gt ltxssimpleTypegt
  ltxsrestriction base"xsstring"gt
  ltxspattern value"malefemale"/gt
  lt/xsrestrictiongt lt/xssimpleTypegt
  lt/xsattributegtlt/xsschemagt

51
XSD The ltanyAttributegt Element

• Myfamily.xml
• lt?xml version"1.0" encoding"ISO-8859-1"?gtltperson
  s xmlns"http//www.microsoft.com"
  xmlnsxsi"http//www.w3.org/2001/XMLSchema-instan
  ce" xsiSchemaLocation"http//www.microsoft.com
  family.xsd http//www.w3schools.com
  attribute.xsd"gtltperson gender"female"gt
  ltfirstnamegtHegelt/firstnamegt ltlastnamegtRefsneslt/l
  astnamegt lt/persongtltperson gender"male"gt
  ltfirstnamegtStalelt/firstnamegt ltlastnamegtRefsneslt
  /lastnamegt lt/persongtlt/personsgt

52
XSD Element Substitution

• With XML Schemas, one element can substitute
  another element.
• Element Substitution Choose Norwegian or English
• ltxselement name"name" type"xsstring"/gt
  ltxselement name"navn" substitutionGroup"name"/gt
  ltxscomplexType name"custinfo"gt
  ltxssequencegt ltxselement ref"name"/gt
  lt/xssequencegt lt/xscomplexTypegtltxselement
  name"customer" type"custinfo"/gt ltxselement
  name"kunde" substitutionGroup"customer"/gt

53
XSD Element Substitution

• ltcustomergt ltnamegtJohn Smithlt/namegt lt/customergt
• ltkundegt ltnavngtJohn Smithlt/navngt lt/kundegt
• Block Element Substitution
• ltxselement name"name" type"xsstring"
  block"substitution"/gt

54
Assignment

• Due on November 20
• Developing an XSD document for your project
• Define your elements format
• Put restrictions on value
• Mininclusive, maxinclusive
• Limit the content Enumeration
• Restrictions on a series of values
• Use default or fixed values
• Be cautious about using the right formats such as
  age element should be positive integer.
• Use indicators
• Sequence, all, choice (at least one of them)
• Minoccurs, maxoccurs
• Use group indicators