[XML-DEV Mailing List Archive Home] [By Thread] [By Date] [Recent Entries] [Reply To This Message] Re: Question on Allowing null values iin DTD
> But I want to allow null values for element? XML does not have null values. It just has character content (#PCDATA) and nested element content (and attributes). If you are wanting to model a database entry that may be null, there are several ways that you may do this, by allowing the element to be empty, or by having an explict child element, say <null/>, or having an explict attribute, it is your choice how to model this in teh XML, and you must then code your application to understand this model. However you chose to model the null value, the DTD declaration will reflect that model, you can't declare "null" in a DTD. > I know that EMPTY element does not allow values. Then what is the purpose of > having EMPTY element in DTD? To declare elements that do not take eleemnt or character content, such as the XHTML img or br elements, both <img/> and <br/> are decared EMPTY. Br often has no attributes either, img should have a src attribute of course but it is still an empty element. David ________________________________________________________________________ This e-mail has been scanned for all viruses by Star. The service is powered by MessageLabs. For more information on a proactive anti-virus service working around the clock, around the globe, visit: http://www.star.net.uk ________________________________________________________________________
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