Question

Is that my XML code valid or not.

<?xml version="1.0"?>
<!DOCTYPE nahrung [
  <!ELEMENT nahrung      (obst|gemuese|sonstiges)+>
  <!ELEMENT obst    (#PCDATA)>
  <!ELEMENT gemuese    (#PCDATA)>
  <!ELEMENT sonstiges    (#PCDATA|beschreibung)*>
  <!ELEMENT beschreibung    EMPTY>
  <!ATTLIST beschreibung artikelname CDATA #REQUIRED
    preis CDATA #REQUIRED>
]>
<nahrung>
    <obst>Pflaume</obst>
    <gemuese>Kohl</gemuese>
    <sonstiges>Keks</sonstiges>
    <sonstiges><beschreibung preis="22.50"
         artikelname="banane"/></sonstiges>
    <gemuese>Gurke Preis: 22.50</gemuese>
</nahrung>

i have a <!ELEMENT nahrung (obst|gemuese|sonstiges)+> that means obst OR gemuse OR sonstiges only one time in xml appear and not all of them altogher.Did I understand correctly?

Answer 1

Your XML looks like it should successfully validate against your DTD – but I don’t think that your DTD matches what you are expecting.

Specifically, this line from your DTD:

<!ELEMENT nahrung      (obst|gemuese|sonstiges)+>

Means that I you must have 1 or more of the elements from that list.

If you only wanted to allow one child element, for example (either obst OR gemuse OR sonstiges), you could use this:

<!ELEMENT nahrung      (obst|gemuese|sonstiges)>