XML Schema Part 0: Primer Second Edition - 0 views
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Attributes may appear once or not at
all, but no other number of times
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<xsd:simpleType name="USStateList">
<xsd:list itemType="USState"/>
</xsd:simpleType>
<xsd:simpleType name="SixUSStates">
<xsd:restriction base="USStateList">
<xsd:length value="6"/>
</xsd:restriction>
</xsd:simpleType>-
USState es una enumeración, definida en este documento en la sección 2.3.
ASí, precisamos siempre de un tipo de dato definido previamente para construir una lista.
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Note that it is possible to derive a list type from the
atomic typestring.
However, astringmay
contain white space, and white space delimits the items in
a list type, so you should be careful using
list types whose base type is
string
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The
include
created schema components "as-is", that is, without any
modification.
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<complexType name="Address">
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base="ipo:Address"
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El tipo base y el extendido tienen igual identificador.
Fuera del elemento "redefine" cualquier intento de nombrar a dos tipos de datos usando el mismo identificador producirá un error.
Notar cómo el elemento "redefine" debe ser el primer hijo del elemento "schema" y encerrar al tipo de dato que redefinimos.
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</redefine>
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The
redefine
element acts very much like theincludeelement as it includes
all the declarations and definitions from theaddress.xsdfile
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Outside of the
redefine
complex type with the same name (and in the same namespace)
as the base from which it is being derived would cause an
error.
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Now that
Addresshas been redefined, the
extension applies to all schema components that make use of
Address-
Cuando un elemento es redefinido, la extensión se aplica a todos los tipos de datos que hacen uso de él como, p.e., sus tipos derivados (ver sección 4.2 y 4.3, así como los ejemplos en Creaweb).
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Elements in a
substitution group must have the same type as the head
element, or they can have a type that has been derived from
the head element's type
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<element name="shipComment" type="string"
substitutionGroup="ipo:comment"/>
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substitutionGroup="ipo:comment"/>
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<ipo:shipComment>
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- no todos los elementos del grupo de sustitución han de aparecer en la instancia XML.
- los indicadores minOccurs y maxOccurs del elemento cabecera deben ser adecuados al número de elementos de sustitución que permitamos aparecer (pueden aparecer tantos como el valor maxOccurs del elemento cabecera).
- si maxOccurs así lo permite, puede aparecer el elemento cabecera y sus sustitutos.
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<ipo:customerComment>
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The existence of a substitution group does not require any
of the elements in that class to be used
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Abstract Elements and Types
XML Schema provides a mechanism to
force substitution for a particular element or type. When
an element or type is declared to be "abstract", it cannot
be used in an instance document. When an element is
declared to be abstract, a member of that element's
substitution group must appear in the instance document.
When an element's corresponding type definition is declared
as abstract, all instances of that element must use
indicate a derived type that is not abstract.
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Declaring an element as abstract requires the use of a
substitution group. Declaring a type as abstract simply
requires the use of a type derived from it (and identified
by the
xsi:type
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abstract="true"
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abstract="true"
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extension base
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extension
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extension
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xsi:type="Car"
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Controlling the Creation & Use of Derived Types
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schema authors will sometimes want
to control derivations of particular types, and the use of
derived types in instances.
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to specify that for a particular complex
type, new types may not be derived from it, either (a) by
restriction, (b) by extension, or (c) at all.
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substitutionGroup=
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The
restrictionvalue of
thefinal
attribute prevents derivations by restriction. Preventing
derivations at all, or by extension, are indicated by the
values#allandextension
respectively
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an optional
finalDefaultattribute
on theschema
element whose value can be one of the values allowed for
thefinal
attribute. The effect of specifying thefinalDefaultattribute
is equivalent to specifying afinalattribute on every type
definition and element declaration in the schema.
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When a simple type is defined, the
fixed
may be applied to any of its facets to prevent a derivation
of that type from modifying the value of the fixed facets.
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fixed="true"
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a mechanism
that controls which derivations and substitution groups may
be used in instance documents
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Previene la sustitución de un elemento por su tipo derivado, bien sea por extensión o restricción.
No confundir este mecanismo con "final", que sólo previene la definición de tipos derivados (por extensión o restricción) de un tipo determinado.
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final="restriction"
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final="restriction"
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final="restriction"
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block="restriction"
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Preventing
replacement by derivations at all, or by
derivations-by-extension, are indicated by the values
#allandextensionrespectively.
As withfinal,
there exists an optionalblockDefaultattribute
on theschema
element whose value can be one of the values allowed for
theblock
attribute.
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mechanism that
enables schema components from different target namespaces
to be used together, and hence enables the schema
validation of instance content defined across multiple
namespaces.
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The
schemaLocation
attribute value consists of one or more pairs of URI references,
separated by white space. The first member of each pair is a namespace
name, and the second member of the pair is a hint describing where to
find an appropriate schema document for that namespace
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there is a
noNamespaceSchemaLocation
used to provide hints for the locations of schema documents
that do not have target namespaces.
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the
includeschemaLocation
attribute, and it contains a URI reference which must
identify a schema document.
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the
importnamespaceandschemaLocation
attributes. If present, theschemaLocation
attribute is understood in a way which parallels the
interpretation of
xsi:schemaLocation
