XML Types

The XML types group includes primitive and derived types that relate to XML document processing. Figure A-4 shows the XSD type hierarchy for this group. As you can see in the figure, all the primitive types appear in ovals.

Figure A-4: The XML type group

Primitive XML Types

The primitive XML types are anyURI, NOTATION, QName, and string.

anyURI

The anyURI type represents the set of all URIs (which is the set of all URLs and URNs) written in accordance with RFCs 2396 and 2732. These can be relative or absolute and include a fragment identifier.

Base Type	Derived Type	SQL Server Type	.NET Type
anySimpleType	N/A	VARCHAR, TEXT, NVARCHAR, or NTEXT	System.String
Applicable Facets	length, minLength, maxLength, pattern, enumeration, whiteSpace
Examples	<uri>http://www.microsoft.com</uri> <uri>urn:uuid:4D36E96A-E325-11CE-BFC1-08002BE10318</uri> <uri>urn:notashop/wscr:AppA</uri>

NOTATION

The NOTATION type represents the XML 1.0 NOTATION type, which is used to identify the format of non-XML data. Note that the NOTATION type cannot be used directly in a schema. You must first derive a type from it using the enumeration facet and then use it only for attributes.

Base Type	Derived Type	SQL Server Type	.NET Type
anySimpleType	N/A	VARCHAR, TEXT, NVARCHAR, or NTEXT	System.String
Applicable Facets	length, minLength, maxLength, pattern, enumeration, whiteSpace
Examples	<xs:simpleType name='mediaPlayers'> <xs:restriction base='xs:NOTATION'> <xs:enumeration value='wmp' /> <xs:enumeration value='real' /> <xs:enumeration value='qcd' /> </xs:restriction> </xs:simpleType>

QName

The QName type represents the set of all fully qualified names that comply with the Namespaces In XML specification. That is, they contain a namespace URI and a local name (an NCName), separated by a colon.

Base Type	Derived Type	SQL Server Type	.NET Type
anySimpleType	N/A	VARCHAR, TEXT, NVARCHAR, or NTEXT	System.Xml. XmlQualifiedName
Applicable Facets	length, minLength, maxLength, pattern, enumeration, whiteSpace
Examples	<QN>xsd:element</QN> <QN>wscr:alongunwieldyQName</QN>

string

The string type represents all finite-length strings of Unicode characters (ISO-10646) that comply with the Char production in XML 1.0.

Base Type	Derived Type	SQL Server Type	.NET Type
anySimpleType	normalizedString	VARCHAR, TEXT, NVARCHAR, or NTEXT	System.String
Applicable Facets	length, minLength, maxLength, pattern, enumeration, whiteSpace
Examples	<str>String</str> <str>99 Pink Elephants</str> <str>Wo ist Himbeerstra e?</str>

Derived XML Types

normalizedString

The normalizedString type represents the set of all white space–normalized characters— that is, all strings that do not contain the carriage return (#xD), line feed (#xA), or tab (#x9) character. To normalize a string containing those characters, you replace those characters with spaces.

Base Type	Derived Type	SQL Server Type	.NET Type
string	token	VARCHAR, TEXT, NVARCHAR, or NTEXT	System.String
Applicable Facets	enumeration, length, maxLength, minLength, pattern, whiteSpace
Examples	<nStr>no line feeds here</nStr> <nStr> pas de weiss spaces </nStr>

token

The token type represents the set of all tokenized strings—all normalized strings (as just described) that have no internal sequence of two or more spaces and no leading or trailing spaces.

Base Type	Derived Type	SQL Server Type	.NET Type
normalizedString	language, NMTOKEN, Name	VARCHAR, TEXT, NVARCHAR, or NTEXT	System.String
Applicable Facets	enumeration, length, maxLength, minLength, pattern, whiteSpace
Examples	<tok>no extraneous spaces here</tok> <tok>pas de weiss spaces</tok>

language

The language type represents the set of all valid language identifiers as given in the XML 1.0 specification. This data type is usually used with attributes.

Base Type	Derived Type	SQL Server Type	.NET Type
token	N/A	VARCHAR, TEXT, NVARCHAR, or NTEXT	System.String
Applicable Facets	enumeration, length, maxLength, minLength, pattern, whiteSpace
Examples	<element lang = "en-GB"/> <element lang = "es" />

NMTOKEN

The NMTOKEN type represents the XML 1.0 NMTOKEN type—all literal values containing one or more of the following characters: a letter, digit, period, comma, underscore, or colon. NMTOKEN should be used only on attributes.

Base Type	Derived Type	SQL Server Type	.NET Type
token	NMTOKENS	VARCHAR, TEXT, NVARCHAR, or NTEXT	System.String
Applicable Facets	enumeration, length, maxLength, minLength, pattern, whiteSpace
Examples	<element NMT="token_of_some_sort" /> <element NMT="but,with,no,spaces" />

NMTOKENS

The NMTOKENS type represents the XML 1.0 NMTOKENS type—all white space– separated lists of NMTOKEN values. NMTOKENS should be used only on attributes.

Base Type	Derived Type	SQL Server Type	.NET Type
NMTOKEN	N/A	N/A	System.String[]
Applicable Facets	enumeration, length, maxLength, minLength, whiteSpace
Examples	<element NMTS="token of some sort" /> <element NMTS="nmtoken1 nmtoken2 nmtoken3" />

Name

The Name type represents the set of all valid XML 1.0 Names.

Base Type	Derived Type	SQL Server Type	.NET Type
token	NCName	VARCHAR, TEXT, NVARCHAR, or NTEXT	System.String
Applicable Facets	enumeration, length, maxLength, minLength, pattern, whiteSpace
Examples	<name>Whizzo_Chocolate</name> <name>asd:some.name</name>

NCName

The NCName type represents the set of all valid XML 1.0 Names that do not contain colons. NCNames are most commonly used as local names for XML elements. NCName stands for noncolonized name.

Base Type	Derived Type	SQL Server Type	.NET Type
Name	ID, IDREF, ENTITY	VARCHAR, TEXT, NVARCHAR, or NTEXT	System.String
Applicable Facets	enumeration, length, maxLength, minLength, pattern, whiteSpace
Examples	<NCN>Crunchy_Frog</NCN> <NCN>no.colons-here</NCN>

ID

The ID type represents the XML ID attribute and the set of all strings that can be used as XML element IDs. This is the set of all valid NCNames.

Base Type	Derived Type	SQL Server Type	.NET Type
NCName	N/A	VARCHAR, TEXT, NVARCHAR, or NTEXT	System.String
Applicable Facets	enumeration, length, maxLength, minLength, pattern, whiteSpace
Examples	<ID>Viking-spam</ID> <ID>Calendar_Header_1</ID>

IDREF

The IDREF type represents the XML IDREF attribute and the set of all strings that can be used as XML element IDs. An XML IDREF must match an ID value elsewhere in the same XML document and should be used only as an attribute value. This schema type set is the set of all valid NCNames.

Base Type	Derived Type	SQL Server Type	.NET Type
NCName	IDREF	VARCHAR, TEXT, NVARCHAR, or NTEXT	System.String
Applicable Facets	enumeration, length, maxLength, minLength, pattern, whiteSpace
Examples	<a ref="Viking-spam" /> <a ref="Calendar_Header_1" />

IDREFS

The IDREFS type represents the XML IDREFS attribute and the set of all finite, nonzero-length space-delimited lists of IDREF strings that can be used as XML element IDs. An XML IDREF must match an ID value elsewhere in the same XML document and should be used only as an attribute value.

Base Type	Derived Type	SQL Server Type	.NET Type
IDREF	N/A	N/A	System.String[]
Applicable Facets	enumeration, length, maxLength, minLength, pattern, whiteSpace
Examples	<a ref="Viking-spam spam_and_chips spam_sandwich" /> <a ref="Calendar_Header_1 Calendar_Header_2" />

ENTITY

The ENTITY type represents the XML ENTITY attribute and the set of all strings that can be used as XML entities. The value given must match an unparsed ENTITY declared elsewhere in the document and should be used only as an attribute. This schema type set is the set of all valid NCNames.

Base Type	Derived Type	SQL Server Type	.NET Type
Name	ENTITIES	VARCHAR, TEXT, NVARCHAR, or NTEXT	System.String
Applicable Facets	enumeration, length, maxLength, minLength, pattern, whiteSpace
Examples	<something /> <something />

ENTITIES

The ENTITIES type represents the XML ENTITIES attribute and the set of all finite, nonzero-length space-delimited lists of ENTITY strings that can be used as XML element IDs. An XML ENTITY must match an ID value elsewhere in the same XML document and should be used only as an attribute value.

Base Type	Derived Type	SQL Server Type	.NET Type
ENTITY	N/A	N/A	System.String[]
Applicable Facets	enumeration, length, maxLength, minLength, pattern, whiteSpace
Examples	<something /> <something />