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Extending DTD

Vijay Venkat
Ranch Hand

Joined: Aug 12, 2001
Posts: 52

Can any one point me to some documents/examples or let me know how i can extend a DTD to add new elements and attributes?

Vijay V
Balaji Loganathan
author and deputy

Joined: Jul 13, 2001
Posts: 3150
The best startup... - DTD tutorial
Vijay Venkat
Ranch Hand

Joined: Aug 12, 2001
Posts: 52
Hi Balaji - Thanks for the Link.

I probably didn't phrase my question right.

I want to know how to Extend a DTD. If someone has already published a DTD and there are few place holders in the DTD where in certain elements allow its child to be of TYPE ANY. In this case i can add new elements there. But ANY in DTD means any element that is already defined in the DTD.
While ANY in schema means a new element, which need not be already declared in the scheam.

So if there is a DTD which has an element say CHEMICAL and has child by name CHEMICAL-EXTENSION which is of type ANY, now in this child element
CHEMICAL-EXTENSION - I want to add new elements which is not defined by the current DTD.

How can i do this. What is the recomended way to do it.

Vijay Venkat
Lasse Koskela

Joined: Jan 23, 2002
Posts: 11962
I haven't done this myself, ever, but I think you should look into the following approach:

1) Leave the existing DTD as it is.
2) Create a new DTD document where you define your new elements.
3) Add an ENTITY reference to the original DTD file...
...and import it into the new DTD file:

Author of Test Driven (2007) and Effective Unit Testing (2013) [Blog] [HowToAskQuestionsOnJavaRanch]
Vijay Venkat
Ranch Hand

Joined: Aug 12, 2001
Posts: 52
Hi Lasse Koskela,
I am back after a break.
Thanks a lot for your response. I will try and let you know how it works.

Vijay Venkat
I agree. Here's the link:
subject: Extending DTD
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