how to create a dtd for this xml?

Question

i have been asked to create a simple dtd for this xml :

<?xml version='1.0' encoding='ISO-8859-1'?>
<QUERY>
  <PORT>
    <NB></NB>
  </PORT>
  <BLOCK>
    <TAB></TAB>
  </BLOCK>
  <STAND>
    <LEVEL></LEVEL>
  </STAND>
</QUERY>

i am using java, i've never did dtd before nor do i know precisely what does it mean. i would like some guidance if its possible, thank you

Answer 1

DTD is Document Type Definition, and is used to represent the structure of you XML document. Other representations include XML Schema, Relax NG, etc.:

• http://en.wikipedia.org/wiki/Document_Type_Definition

It will look something like the following (although my syntax may not be quite right):

<!ELEMENT QUERY (PORT, BLOCK, STAND)>
<!ELEMENT PORT (NB)>
<!ELEMENT NB (#PCDATA)>
<!ELEMENT BLOCK (TAB)>
<!ELEMENT TAB (#PCDATA)>
<!ELEMENT STAND (LEVEL)>
<!ELEMENT LEVEL (#PCDATA)>

If you look at the definition for QUERY you see it defines that it contains the elements: "PORT", "BLOCK", and "STAND". If you look at the definition for NB, we have declared that it should contain text (parsed character data).