Question

this is getting to my brain so i have a XML doc that has a node called family

<family>
  <parents>
    <name>Bob</name>
    <init>R</init>
    <surname>Johnson</surename>
  </parents>
  <kids>
    <name>Lucy</name>
    <surname>Johnson</surname>
  </kids>
</family>

the inital is optional so i create the DTD for this it ends up looking like

<!ELEMENT parent (name, initial?, surname)>
<!ELEMENT kid (name, initial?, surname)>
<!ELEMENT name (#PCDATA)>
<!ELEMENT initial (#PCDATA)>
<!ELEMENT surname (#PCDATA)>
<!ELEMENT name (#PCDATA)>
<!ELEMENT initial (#PCDATA)>
<!ELEMENT surname (#PCDATA)>

but i keep getting this error validity error : Redefinition of element name ^ /tmp/tmp.dtd:26: validity error : Redefinition of element initial ^ /tmp/tmp.dtd:27: validity error : Redefinition of element surname ^

even if i change the DTD to look like this.

<!ELEMENT parent (name, initial?, surname)>
<!ELEMENT name (#PCDATA)>
<!ELEMENT initial (#PCDATA)>
<!ELEMENT surname (#PCDATA)>
<!ELEMENT kid (name, initial?, surname)>
<!ELEMENT name (#PCDATA)>
<!ELEMENT initial (#PCDATA)>
<!ELEMENT surname (#PCDATA)>

same error.. this is literally the second day i am using xml and from the tutorials i have read i cant seem to see what i am doing wrong..

Answer 1

You don’t need to declare the name, initial and surname twice, just try

<!ELEMENT parent (name, initial?, surname)>
<!ELEMENT kid (name, initial?, surname)>
<!ELEMENT name (#PCDATA)>
<!ELEMENT initial (#PCDATA)>
<!ELEMENT surname (#PCDATA)>

parent and kid share the same definitions for their three (or two) child elements. Given an additional definition of

<!ELEMENT family (parent*, kid*)>

this would validate the following (corrected from the document you included in the question)

<family>
  <parent>
    <name>Bob</name>
    <initial>R</initial>
    <surname>Johnson</surname>
  </parent>
  <kid>
    <name>Lucy</name>
    <surname>Johnson</surname>
  </kid>
</family>