使用DTD可以指定元素出现的确切数目吗? [英] Using DTD can I specify an exact number of element occurrences?
问题描述
我正在尝试使用XML进行此练习,但我停留在这一特定点。我被要求创建一个满足要求列表的DTD,但我找不到实现以下条件的方法:
I am trying to do this exercise in XML and I am stuck at this particular point. I am being asked to create a DTD that will satisfy a list of requirements and I cannot find a way to achieve the following:
季节性价格'列表中可能没有,一,两个或三个出现过'season_price'元素
The seasonal_prices' list can have none, one, two or three occurrences of the 'season_price' element
有没有一种方法可以使用<
Is there a way to achieve this using only a DTD?
推荐答案
有没有一种方法可以使用仅 DTD?
Is there a way to achieve this using only a DTD?
不。
您只能这样做:
-
season_price
(恰好是一个) -
季节价格?
(零或一个) -
season_price +
(一个或多个) -
season_price *
(零或更多)
season_price
(exactly one)season_price?
(zero or one)season_price+
(one or more)season_price*
(zero or more)
请参见 https://www.w3.org/TR/xml11/#sec-element-content 了解更多信息。
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就像您在另一个问题,您可以 >使用执行此操作吗?
,例如:
Like you mentioned in another question, you could do this using ?
like:
<!ELEMENT seasonal_prices (season_price?, season_price?, season_price?)>
但是没有XML Schema(minOccurs / maxOccurs)这样的直接方法。
but there's no direct way like in XML Schema (minOccurs/maxOccurs).
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