Element schematu XML Element

Definicja i użycie

Element element definiuje element.

Informacje o elemencie

Elementy nadrzędne: schemat, wybór, wszystko, kolejność, grupa

Składnia

(Znak ? deklaruje, że element może wystąpić zero lub jeden raz, a znak * deklaruje, że element może wystąpić zero lub więcej razy wewnątrz elementu)

Attribute	Description
id	Optional. Specifies a unique ID for the element
name	Optional. Specifies a name for the element. This attribute is required if the parent element is the schema element
ref	Optional. Refers to the name of another element. The ref attribute can include a namespace prefix. This attribute cannot be used if the parent element is the schema element
type	Optional. Specifies either the name of a built-in data type, or the name of a simpleType or complexType element
substitutionGroup	Optional. Specifies the name of an element that can be substituted with this element. This attribute cannot be used if the parent element is not the schema element
default	Optional. Specifies a default value for the element (can only be used if the element's content is a simple type or text only)
fixed	Optional. Specifies a fixed value for the element (can only be used if the element's content is a simple type or text only)
form	Optional. Specifies the form for the element. "unqualified" indicates that this element is not required to be qualified with the namespace prefix. "qualified" indicates that this element must be qualified with the namespace prefix. The default value is the value of the elementFormDefault attribute of the schema element. This attribute cannot be used if the parent element is the schema element
maxOccurs	Optional. Specifies the maximum number of times this element can occur in the parent element. The value can be any number >= 0, or if you want to set no limit on the maximum number, use the value "unbounded". Default value is 1. This attribute cannot be used if the parent element is the schema element
minOccurs	Optional. Specifies the minimum number of times this element can occur in the parent element. The value can be any number >= 0. Default value is 1. This attribute cannot be used if the parent element is the schema element
nillable	Optional. Specifies whether an explicit null value can be assigned to the element. True enables an instance of the element to have the null attribute set to true. The null attribute is defined as part of the XML Schema namespace for instances. Default is false
abstract	Optional. Specifies whether the element can be used in an instance document. True indicates that the element cannot appear in the instance document. Instead, another element whose substitutionGroup attribute contains the qualified name (QName) of this element must appear in this element's place. Default is false
block	Optional. Prevents an element with a specified type of derivation from being used in place of this element. This value can contain #all or a list that is a subset of extension, restriction, or equivClass: extension - prevents elements derived by extension restriction - prevents elements derived by restriction substitution - prevents elements derived by substitution #all - prevents all derived elements
final	Optional. Sets the default value of the final attribute on the element element. This attribute cannot be used if the parent element is not the schema element. This value can contain #all or a list that is a subset of extension or restriction: extension - prevents elements derived by extension restriction - prevents elements derived by restriction #all - prevents all derived elements
any attributes	Optional. Specifies any other attributes with non-schema namespace

Przykład 1

Poniższy przykład to schemat z czterema prostymi elementami o nazwach „fname”, „lname”, „age” i „dateborn”, które są typu string, nonNegativeInteger i date:

<?xml version="1.0"?>
<xs:schema xmlns:xs="http://www.w3.org/2001/XMLSchema">

<xs:element name="fname" type="xs:string"/>
<xs:element name="lname" type="xs:string"/>
<xs:element name="age" type="xs:nonNegativeInteger"/>
<xs:element name="dateborn" type="xs:date"/>

</xs:schema>

Przykład 2

Poniższy przykład to schemat z elementem o nazwie „notatka”, który jest typu złożonego. Element „notatka” zawiera cztery inne proste elementy; „do”, „od”, „nagłówek” i „ciało”:

<?xml version="1.0"?>
<xs:schema xmlns:xs="http://www.w3.org/2001/XMLSchema">

<xs:element name="note">
  <xs:complexType>
    <xs:sequence>
      <xs:element name="to" type="xs:string"/>
      <xs:element name="from" type="xs:string"/>
      <xs:element name="heading" type="xs:string"/>
      <xs:element name="body" type="xs:string"/>
    </xs:sequence>
  </xs:complexType>
</xs:element>

</xs:schema>

Przykład 3

Ten przykład jest całkiem taki sam jak w przykładzie 2, ale tutaj wybraliśmy użycie atrybutu ref do odwoływania się do nazw elementów:

<?xml version="1.0"?>
<xs:schema xmlns:xs="http://www.w3.org/2001/XMLSchema">

<xs:element name="note">
  <xs:complexType>
    <xs:sequence>
      <xs:element ref="to"/>
      <xs:element ref="from"/>
      <xs:element ref="heading"/>
      <xs:element ref="body"/>
    </xs:sequence>
  </xs:complexType>
</xs:element>

<xs:element name="to" type="xs:string"/>
<xs:element name="from" type="xs:string"/>
<xs:element name="heading" type="xs:string"/>
<xs:element name="body" type="xs:string"/>

</xs:schema>

❮ Pełne odniesienie do schematu XML

Samouczek XML

XML AJAX

XML DOM

Samouczek XPath

Samouczek XSLT

Samouczek XQuery

XML DTD

Schemat XSD

Kompleks XSD

Dane XSD

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