XML Schema minOccurs/maxOccurs 默认值 [英] XML Schema minOccurs / maxOccurs default values

问题描述

我想知道 XML Schema 规范如何处理这些情况:

I'm wondering how the XML Schema specification handles these cases:

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

没有给出 maxOccurs -> 这是基数 [1..1] 吗?

No maxOccurs given -> Is this the cardinality [1..1]?

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

我认为这根本无效?

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

这是基数 [0..2] 还是 [1..2]?

Is this the cardinality [0..2] or [1..2]?

是否有关于 XML Schema 规范如何处理这些情况的官方"定义?

Is there an "official" definition on how the XML Schema spec handles these cases?

推荐答案

minOccurs 和 maxOccurs 的默认值为 1.因此:

The default values for minOccurs and maxOccurs are 1. Thus:

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

基数为 [1-1] 注意:如果指定only minOccurs 属性，则它不能大于 1，因为 maxOccurs 的默认值为 1.

cardinality is [1-1] Note: if you specify only minOccurs attribute, it can't be greater than 1, because the default value for maxOccurs is 1.

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

无效

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

基数是[1-2] 注意:如果你指定only maxOccurs 属性，它不能小于1，因为minOccurs 的默认值是1.

cardinality is [1-2] Note: if you specify only maxOccurs attribute, it can't be smaller than 1, because the default value for minOccurs is 1.

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

是使元素被禁止的有效组合.

is a valid combination which makes the element prohibited.

有关更多信息，请参阅http://www.w3.org/TR/xmlschema-0/#OccurrenceConstraints

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