posted 20 years ago
DTDs can either be internal or external. I think the advantages comes with an internal dtd.
1) Lesser roundtrips to the server:
If the DTD is included in the instance document, the parser need not send a request back to the server to fetch the DTD or schema for validating the instance document. (Not considering public identified DTDs or those that are cached.)
2) Validation can be changed at runtime.
Since the internal DTD subset overrides the external DTD, it can be used for changing the validation rules at runtime in the instance document (This can also be looked at as a disadvantage.)
I am sure this is not convincing, but, I hope these might be some reasons why we may want to have DTDs.
Any suggestions??
Karthik Jayaraman.<br />IBM Certified Developer - XML and Related Technologies.<br />Sun Certified Developer for java WebServices.<br />Sun Certified Java Programmer.