Hi, these are from PXML2:
...an external DTD need not be a separate file - it could be stored as a record contained in a databse...
I don't know what it means, if this external DTD is stored as a record, how could we associate it with the internal subset?
...the external subset description of an element might allow several child elements, while the internal subset version specifies an empty element. Any XML data containing this DTD combination had better use an empty element, or it would be considered invalid.
Why does it say "it would be considered invalid"? The same element in the internal set can override the one in the external set, right? Pretty confusing.
Could anyone explain these to me? Thanks.