Basic XML questions...

[Unal]

Hi,

I have couple of simple questions about XML that I cannot find answers to in the book I looked at and in the search I did on internet. Can anyone help me with these?

1- Why is XML case sensitive?
2- Why does not XML allow tag minimization?
3- Why must XML document elements be properly nested?
4- Can you put binary data in a CDATA section?
5- Is there any limit to the length of an element or attribute name? 6- Where do you declare entities? 7- In XML, which takes precedence, the internal DTD or the external DTD?

TIA,
Unal.

 

[Richard Tobin]

I have couple of simple questions about XML that I cannot find answers to in the book I looked at and in the search I did on internet.

These do not seem like plausible questions for a real user to ask. On the contrary, they look just like homework exercises.

In any case, you can find most of the answers in the XML specification itself.

-- Richard

 

[Jeff Kish]

Hi,

I have couple of simple questions about XML that I cannot find answers to in the book I looked at and in the search I did on internet. Can anyone help me with these?

1- Why is XML case sensitive?
2- Why does not XML allow tag minimization?

I don't know.. maybe because XML is an SGML instance?

3- Why must XML document elements be properly nested?
4- Can you put binary data in a CDATA section?

This certainly is answered a zillion places, and even in this newsgroup!.. err after that harangue, I hope this is correct.. yes you can but it has to be encoded to be valid XML text... sort of like bin2hex does.

5- Is there any limit to the length of an element or attribute name?

Maybe this is implementation dependent.. seems the perfect place to look for an answer is the spec.

6- Where do you declare entities?
7- In XML, which takes precedence, the internal DTD or the external DTD?

I've never used an internal DTD..
try making a test document and find out.

TIA,
Unal.

HTH

 

[Peter Flynn]

Hi,

I have couple of simple questions about XML that I cannot find answers to in the book I looked at and in the search I did on internet. Can anyone help me with these?

Did you try reading the FAQ at http://www.ucc.ie/xml ?

1- Why is XML case sensitive?

So that languages using alphabets which have no case can be used. If we had allowed case-insensitivity, it would preclude some people from using it. (Actually it was more complex than that, but it will suffice).

2- Why does not XML allow tag minimization?

To make it easier to write programs for.

3- Why must XML document elements be properly nested?
Ditto.

4- Can you put binary data in a CDATA section?

No. Use UUencoding or Base64 or something like.

5- Is there any limit to the length of an element or attribute name?

In theory, no. In the formal definitions, 999999999 I think. In practice, I suspect many systems will explode into little pieces of pink goo if you try to make them read strings longer than their virtual memory maxima.

6- Where do you declare entities?

In the DTD or internal subset.

7- In XML, which takes precedence, the internal DTD or the external DTD?

The internal subset is read and processed before the external subset. That way you can include declarations (eg of entities) which will prevent others of the same name from being used, and thus take precedence. Many large DTDs use this to allow on-the-fly modifications by overriding portions of the external subset whose use or non-use is controlled by a Parameter Entity.

///Peter