Thank you for the helpful replies to my questions.

Girish Sharma

"Girish Sharma" <remvgirish.sharma@e...> wrote in message 
news:2ooUf.5961$x94.4248@n......
> I'm new to using XML. I am currently required to use dtd's rather than 
> schemas. I have some questions about what is considered appropriate design 
> with a dtd. It seems that none of the following are enforced by the dtd 
> during a standard validation:
>
> 1. Using the value of attributes to constrain which of the optional child 
> elements are allowed to be used.
>
> 2. Restricting the number of a particular element that can exist with a 
> particular attribute value.
>
> 3. Restricting which of some optional child elements are allowed based on 
> the context (the grand-parent element) of the parent element.
>
> Is creating a dtd that uses these concepts, even though they are not 
> enforced during standard validation, considered less than optimal design?
>
> Are there commonly used alternatives to the above that do allow for dtd 
> enforcement?
>
> I'm wondering for example for number 1, instead of attribute values using 
> optional child elements that correspond with each of those values. Then 
> each of those child elements can in turn can have the desired child 
> elements for that situation. It could result in a large number of the 
> "intermediate" child elements if there are many possible attribute values.
>
> For number 2, is there any way to accomplish that using child elements 
> instead of attribute values?
>
> For number 3, it seems that changing the parent element into several 
> similar elements and then using the appropriate one in the correct 
> context. If carried to an extreme though, there would be no optional child 
> elements at all - only different parent elements. But my question relates 
> specifically about always being required to use particular optional child 
> elements based on context.
>
> Thank you.
>
> Girish Sharma
>