K2 BLACKPEARL PRODUCT DOCUMENTATION: USER GUIDE
XML Data Types

K2 Concepts - XML Data Types

XML Schemas support Built-In Data Types and User Defined Data Types to assist with the data validation of the input text strings.

XML Schemas divide user defined data types into two broad categories: simple and complex:

This topic also considers:

Basic Data Types

 The following table lists all the basic data types supported by XML:

Built-in XML Data Types
Type Description Type Description
string Any character normalizedString A whitespace normalized string where all spaces, tabs, carriage return and line feed characters are converted to single spaces
token A string that does not contain a sequence of two or more spaces, tabs, carriage return and line feed characters byte A numeric value from -128 to 127
unsignedByte A numeric value from 0 to 255 hex64Binary Base 64 encoded binary information
hexBinary Hexidecimally encoded binary information integer A numeric value representing a whole number
positiveInteger An integer whose value is greater than 0 negativeInteger An integer whose value is less than 0
nonNegativeInteger An integer whose value is 0 or greater than 0 nonPositiveInteger An integer whose value is 0 or less than 0
int A numeric value from -2 147 483 648 to 2 147 483 647 unsignedInt A numeric value from 0 to 4 294 967 295
long A numeric value from -9 223 372 036 854 775 808 to 9 223 372 036 854 775 807 unsignedLong A numeric value from 0 to 18 446 744 073 709 551 615
short A numeric value from -32 768 to 32 767 unsignedShort A numeric value from 0 to 65 535
decimal A numeric value that may or may not contain a fractional part float Any 32-bit floating-type real number
e.g. 1E4, 1267.43233E12, 12.78e-2, 12
double Any 64-bit floating-type real number
e.g. 1E4, 1267.43233E12, 12.78e-2, 12		 Boolean A logical value including True, False, 0 and 1
time An instant of time that recurs everyday in the format HH:MM:SS e.g.12:30:00, this time references UTC (Coordinated Universal Time) date Date value in the format YYYY-MM-DD
dateTime A combine date and time value in the format YYYY-MM-DD HH:MM:SS duration Length of a time interval in the extended format
e.g.P1Y1M1D1H1M1S = 1 Year + 1 Month + 1 Day + 1 Hour + 1 Minute +1 Second
gMonth A Gregorian (Calendar) Month, the month (MM) part of a Date gYear A Gregorian (Calendar) Year, the year (YYYY) part of a Date
gYearMonth A Gregorian Year and Month, the year-month (YYYY-MM) part of a Date gDay A Gregorian Day, the day (DD) part of a Date
gMonthDay A specific day of the month, the month-day (MM-DD) part of a Date Name A string based on a well-formed element and attribute naming rules
QName The fully qualified XML Namespace name e.g. if the namespace is defined as
xmlns:html="http://www.w3.org/1999/xhtml" the qualified name for <html:p> resolves to {http://www.w3.org/1999/xhtml}p		 NCName The part of the namespace name to the right of the namespace prefix and colon e.g. if the namespace is defined as xmlns:html="http://www.w3.org/1999/xhtml" the NCName would be html="http://www.w3.org/1999/xhtml"
anyURI Represents the URI (Universal Resource Identifier) and can contain a URL or URN language A language constant as defined in RFC 1766, e.g. en-us (RFC 1766, ISO 639 Language Codes) (accessed September 2005)

Simple Types

A simpleType declaration follows the format:

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<--Basic declaration-->

<declarationPrefix:simpleType id=ID final=(#all|(list|union|restriction)) name=NCName>
Content:(annotation?, (restriction|list|union))</declarationPrefix:simpleType>

<--Declaration of a restriction-->

<declarationPrefix:restriction base=QName>
Content:(annotation?, (simpleType?,(minExclusive|minInclusive|maxExclusive|maxInclusive|totalDigits|fractionDigits|length|minLength|maxLength
|enumeration|whiteSpace|pattern)))</declarationPrefix:restriction>

<--Declaration of a list-->

<declarationPrefix:list base=QName>
Content:(annotation?, (simpleType?))</declarationPrefix:list>

<--Declaration of a union-->

<declarationPrefix:union base=QName>
Content:(annotation?, (simpleType))</declarationPrefix:union>

 For more details on further options see www.xml.dvint.com/docs/SchemaDataTypesQR-1.pdf (accessed September 2005)

 Although the simpleType declaration format seems very confusing  they follow a simple structure:

  1. id - provides a unique identifier to element
  2. final - restricts how new data types may be derived from this simpleType:
  1. name - - the name of the data type this element is defining
Constraining Factors in XML
Type Description
length Number of characters or for lists number of list choices
minLength Minimum number of characters or minimum number of list choices for lists
maxLength Maximum number of characters or maximum number of list choices for lists
pattern Defines a pattern or sequence of acceptable characters
enumeration Restricts the allowed values to a set of specified values
whitespace Sets how line feeds, tabs, spaces, and carriage returns are treated when the document is parsed
maxInclusive Maximum value including the number specified
minInclusive Minimum value including the number specified
maxExclusive Maximum value excluding the number specified
minExclusive Minimum value excluding the number specified
totalDigits Number of digits allowed for the non-decimal part of a decimal number (must be a positive number)
fractionDigits Number of digits allowed for the non-decimal part of a decimal number (must be a non-negative number)

The structure is often best understood in an example:

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<--XML Type Declaration-->

<?xml version="1.0" encoding="UTF-8">

<--XML Schema Declaration-->

<xsd:schema xmlns:xsd="http://www.w3.org/2001/xmlschema">

<--Simple Type Element Declaration-->

<xsd:simpleType name="my_day_of_month">

<--Declaration of Restriction Base and Conditions-->

  <xsd:restriction base="xsd:positiveInteger">
    <xsd:maxInclusion value="31" />
  </xsd:restriction>
</xsd:simpleType>

<--Another Simple Type Element Declaration-->

<xsd:simpleType name="numeric_postal_code">

<--Declaration of Restriction Base and Conditions-->

  <xsd:restriction base="xsd:integer">
    <xsd:minInclusion value="1000" />
    <xsd:maxInclusion value="9999" />
  </xsd:restriction>
</xsd:simpleType>

</xsd:schema>

</?xml>

Complex Types

The ability to define complex data types in XML is one of its most powerful features.

A complex type element declaration is used to describe data collections and choices.

A complex type definition is most easily understood as a set of data variables  - elements - and a content model (which is a combination construct).

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<--XML Type Declaration-->

<?xml version="1.0" encoding="UTF-8">

<--XML Schema Declaration-->

<xsd:schema xmlns:xsd="http://www.w3.org/2001/xmlschema">

<--Complex Type Element Declaration-->

<xsd:complexType name="contactDetails">

<--Specifying the Content Model-->

  <xsd:sequence>

<--Listing the Elements-->

    <xsd:element name="firstName" type="xsd:string" minOccurs="1" maxOccurs="unbounded" />
    <xsd:element name="lastName" type="xsd:string" />
    <xsd:element name="email" type="xsd:string" minOccurs="0" maxOccurs="1" />
    <xsd:element name="telephone" type="xsd:string" minOccurs="0" maxOccurs="2" />
    <xsd:element name="cellphone" type="xsd:string" />
  </xsd:sequence>

<--Listing the Attributes-->

  <xsd:attribute name="title" type="xsd:string" use="optional" />
  <xsd:attribute name="position" type="xsd:string" use="required" />

</xsd:complexType>

Elements can be combined using the following content models:

The number of values each element is specified using the minOccurs and maxOccurs variables - these can be any non-negative integer. Similarly specifying minOccurs="0" defines the element as being optional. The Occurrence Constraints are further discussed in XML Schema

Attributes are defined as usual, with the additional Use Constraints if the attribute is required or optional

Both simpleType and complexType elements can be constrained using a data restriction

Extending Data Definitions

All data definitions in XML can be extended. The following example extends the contactDetails definition above.

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<--Specifying the New Data Set Definition Name-->

<xsd:complexType name="extendedContactDetails">

<--Specifying Data Definition being Extended-->

  <xsd:extension base="contactDetails">

<--Specifying the Content Model-->

    <xsd:sequence>

<--Listing the New Elements-->

      <xsd:element name="address" type="xsd:string" />
      <xsd:element name="city" type="xsd:string" />
      <xsd:element name="country" type="xsd:string" />

    </xsd:sequence>
  </xsd:extension>
</xsd:complexType>

Element Context - Content Types

XML data definitions are able to relate awareness of the context in which they will be used by specifying content types.

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<--Data Type Declaration: Order Confirmation, note mixed declaration-->

<xsd:complexType name="orderConfirmation" mixed="true">

  <xsd:extension base="extendedContactDetails">

<--Specifying the Content Model-->

    <xsd:sequence>

<--Listing the New Elements-->

      <xsd:element name="orderId" type="xsd:positiveInteger">
      <xsd:element name="shipDate" type="xsd:date">

    </xsd:sequence>
  </xsd:extension>
</xsd:complexType>

<--Using the Order Confirmation Data Type-->

<orderConfirmation>

Dear <firstName>John Smith</firstName>
Your order <orderId>01267</orderId>
will be shipped on <shipDate>20 September 2005</shipDate>
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<--Shorthand for an Empty Complex Data Type-->

<xsd:complexType name="internationalPrice">

<--List Attributes Only-->

  <xsd:attribute name="currency" type="xsd:string" />
  <xsd:attribute name="value" type="xsd:decimal" />

</xsd:complexType>
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<--Declared anyType Data Type-->

<xsd:element name="anything" type="xsd:anyType" />

<--No Type Declaration - default anyType-->

<xsd:element name="anything" />

 

 

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