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xmldtd

Using DTD can I specify an exact number of element occurrences?

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:

The seasonal_prices' list can have none, one, two or three occurrences of the 'season_price' element

Is there a way to achieve this using only a DTD?

Solution

  • Is there a way to achieve this using only a DTD?

    Nope.

    You can only do:

    • season_price (exactly one)
    • season_price? (zero or one)
    • season_price+ (one or more)
    • season_price* (zero or more)

    See https://www.w3.org/TR/xml11/#sec-element-content for more info.

    ----- Edit -----

    Like you mentioned in another question, you could do this using ? like:

    <!ELEMENT seasonal_prices (season_price?, season_price?, season_price?)>

    but there's no direct way like in XML Schema (minOccurs/maxOccurs).