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XML Schema minOccurs / maxOccurs默认值

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我想知道XML Schema规范如何处理这些情况：

<xsd:element minOccurs="1" name="asdf"/>

没有给出maxOccurs - >这是基数[1..1]吗？

<xsd:element minOccurs="5" maxOccurs="2" name="asdf"/>

我想这简直无效了？

<xsd:element maxOccurs="2" name="asdf"/>

这是基数[0..2]还是[1..2]？

是否有关于XML Schema规范如何处理这些案例的“官方”定义？

xml xsd

4 回答

  • 0

    minOccurs 和 maxOccurs 的默认值为1.因此：

    <xsd:element minOccurs="1" name="asdf"/>

    基数为[1-1]注意：如果只指定minOccurs属性，则不能大于1，因为maxOccurs的默认值为1 .

    <xsd:element minOccurs="5" maxOccurs="2" name="asdf"/>

    无效

    <xsd:element maxOccurs="2" name="asdf"/>

    基数为[1-2]注意：如果只指定maxOccurs属性，则不能小于1，因为minOccurs的默认值为1 .

    <xsd:element minOccurs="0" maxOccurs="0"/>

    是一个有效的组合，使元素被禁止 .

    有关详细信息，请参阅http://www.w3.org/TR/xmlschema-0/#OccurrenceConstraints

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  • 47

    一个旧的，常见问题的新的，扩展的答案......

    默认值

    • 发生限制 minOccurs 和 maxOccurs default to 1 .

    常见案例解释

    <xsd:element name="A"/>

    表示 A 是 required ，必须出现 exactly once .

    <xsd:element name="A" minOccurs="0"/>

    表示 A 是 optional ，可能会出现 at most once .

    <xsd:element name="A" maxOccurs="unbounded"/>

    表示 A 是 required 并且可能重复 unlimited number of times .

    <xsd:element name="A" minOccurs="0" maxOccurs="unbounded"/>

    表示 A 是 optional 并且可能重复 unlimited number of times .

    另请参阅

    通常，当minOccurs的值为1或更大时，需要显示一个元素 . 元素可能出现的最大次数由其声明中maxOccurs属性的值确定 . 该值可以是正整数，例如41，或者术语无界，表示没有最大出现次数 . minOccurs和maxOccurs属性的默认值为1.因此，当声明没有maxOccurs属性的注释等元素时，该元素可能不会出现多次 . 请确保如果仅为minOccurs属性指定值，则它小于或等于maxOccurs的默认值，即它是0或1.同样，如果仅为maxOccurs属性指定值，则必须为大于或等于minOccurs的默认值，即1或更多 . 如果省略这两个属性，则元素必须只出现一次 .

    <element
  maxOccurs = (nonNegativeInteger | unbounded)  : 1
  minOccurs = nonNegativeInteger : 1
  >

</element>
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  • 298

    例：

    XML

    <?xml version="1.0" encoding="UTF-8"?> 
<?xml-stylesheet type="text/xsl" href="country.xsl"?>
<country xmlns:xsi="http://www.w3.org/2001/XMLSchema-instance" xsi:noNamespaceSchemaLocation="country.xsd">
    <countryName>Australia</countryName>
    <capital>Canberra</capital>
    <nationalLanguage>English</nationalLanguage>
    <population>21000000</population>
    <currency>Australian Dollar</currency>
    <nationalIdentities>
        <nationalAnthem>Advance Australia Fair</nationalAnthem>
        <nationalDay>Australia Day (26 January)</nationalDay>
        <nationalColour>Green and Gold</nationalColour>
        <nationalGemstone>Opal</nationalGemstone>
        <nationalFlower>Wattle (Acacia pycnantha)</nationalFlower>
    </nationalIdentities>
    <publicHolidays>
        <newYearDay>1 January</newYearDay>
        <australiaDay>26 January</australiaDay>
        <anzacDay>25 April</anzacDay>
        <christmasDay>25 December</christmasDay>
        <boxingDay>26 December</boxingDay>
        <laborDay>Variable Date</laborDay>
        <easter>Variable Date</easter>
        <queenBirthDay>21 April (Variable Date)</queenBirthDay>
    </publicHolidays>
    <states>
        <stateName><Name>NSW -  New South Wales</Name></stateName>
        <stateName><Name>VIC -  Victoria</Name></stateName>
        <stateName><Name>QLD -  Queensland</Name></stateName>
        <stateName><Name>SA -  South Australia</Name></stateName>
        <stateName><Name>WA -  Western Australia</Name></stateName>
        <stateName><Name>TAS -  Tasmania</Name></stateName>
    </states>
    <territories>
        <territoryName>ACT -  Australian Capital Territory</territoryName>
        <territoryName>NT -  Northern Territory</territoryName>
    </territories>
</country>

    XSD：

    <?xml version="1.0" encoding="UTF-8"?> 
<xs:schema xmlns:xs="http://www.w3.org/2001/XMLSchema">
    <xs:element name="country">
        <xs:complexType>
            <xs:sequence>
                <xs:element name="countryName" type="xs:string"/>
                <xs:element name="capital" type="xs:string"/>
                <xs:element name="nationalLanguage" type="xs:string"/>
                <xs:element name="population" type="xs:double"/>
                <xs:element name="currency" type="xs:string"/>
                <xs:element name="nationalIdentities">
                <xs:complexType>
                    <xs:sequence>
                        <xs:element name="nationalAnthem" type="xs:string"/>
                        <xs:element name="nationalDay" type="xs:string"/>
                        <xs:element name="nationalColour" type="xs:string"/>
                        <xs:element name="nationalGemstone" type="xs:string"/>
                        <xs:element name="nationalFlower" type="xs:string"/>
                    </xs:sequence>
                </xs:complexType>
                </xs:element>
                <xs:element name="publicHolidays">
                    <xs:complexType>
                        <xs:sequence>
                            <xs:element name="newYearDay" maxOccurs="1" type="xs:string"/>
                            <xs:element name="australiaDay" maxOccurs="1" type="xs:string"/>
                            <xs:element name="anzacDay" maxOccurs="1" type="xs:string"/>
                            <xs:element name="christmasDay" maxOccurs="1" type="xs:string"/>
                            <xs:element name="boxingDay" maxOccurs="1" type="xs:string"/>
                            <xs:element name="laborDay" maxOccurs="1" type="xs:string"/>
                            <xs:element name="easter" maxOccurs="1" type="xs:string"/>
                            <xs:element name="queenBirthDay" maxOccurs="1" type="xs:string"/>
                        </xs:sequence>
                    </xs:complexType>
                </xs:element>
                <xs:element name="states">
                    <xs:complexType>
                        <xs:sequence>
                            <xs:element name="stateName" minOccurs="1" maxOccurs="unbounded">
                                <xs:complexType>
                                    <xs:sequence>
                                        <xs:element name="Name" type="xs:string"/>
                                    </xs:sequence>
                                </xs:complexType>
                            </xs:element>
                        </xs:sequence>
                    </xs:complexType>
                </xs:element>
                <xs:element name="territories">
                    <xs:complexType>
                        <xs:sequence>
                            <xs:element name="territoryName" maxOccurs="unbounded"/>
                        </xs:sequence>
                    </xs:complexType>
                </xs:element>
            </xs:sequence>
        </xs:complexType>
    </xs:element>
</xs:schema>

    XSL：

    <?xml version="1.0"?> 
<xsl:stylesheet xmlns:xsl="http://www.w3.org/1999/XSL/Transform" version="1.0">
    <xsl:output method="html" indent="yes" version="4.0"/>
    <xsl:template match="/">
        <html>
            <body>          
                <xsl:for-each select="country">         
                    <xsl:value-of select="countryName"/>
    
                    <xsl:value-of select="capital"/>
    
                    <xsl:value-of select="nationalLanguage"/>
    
                    <xsl:value-of select="population"/>
    
                    <xsl:value-of select="currency"/>
                  
                    <xsl:for-each select="nationalIdentities">
                        <xsl:value-of select="nationalAnthem"/>
    
                        <xsl:value-of select="nationalDay"/>
    
                        <xsl:value-of select="nationalColour"/>
    
                        <xsl:value-of select="nationalGemstone"/>
    
                        <xsl:value-of select="nationalFlower"/>
    
                    </xsl:for-each>
                    <xsl:for-each select="publicHolidays">
                        <xsl:value-of select="newYearDay"/>
    
                        <xsl:value-of select="australiaDay"/>
    
                        <xsl:value-of select="anzacDay"/>
    
                        <xsl:value-of select="christmasDay"/>
    
                        <xsl:value-of select="boxingDay"/>
    
                        <xsl:value-of select="laborDay"/>
    
                        <xsl:value-of select="easter"/>
    
                        <xsl:value-of select="queenBirthDay"/>
    
                    </xsl:for-each>
                    <xsl:for-each select="states/stateName">
                        <xsl:value-of select="Name"/>
    
                    </xsl:for-each>
                </xsl:for-each>
            </body>
        </html>
    </xsl:template>
</xsl:stylesheet>

    Result:

    Australia
Canberra
English
21000000
Australian Dollar
Advance Australia Fair
Australia Day (26 January)
Green and Gold
Opal
Wattle (Acacia pycnantha)
1 January
26 January
25 April
25 December
26 December
Variable Date
Variable Date
21 April (Variable Date)
NSW - New South Wales
VIC - Victoria
QLD - Queensland
SA - South Australia
WA - Western Australia
TAS - Tasmania
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  • 0

    Short answer:

    正如xsd中所写：

    <xs:attribute name="minOccurs" type="xs:nonNegativeInteger" use="optional" default="1"/>
<xs:attribute name="maxOccurs" type="xs:allNNI" use="optional" default="1"/>

    如果提供带数字的属性，则数字为边界 . Otherwise attribute should appear exactly once .

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