Hi George!

Thanks a lot for the reply, it is greatly appreciated and I will look
into this immediately!

With best regards, Stefan

George Bina wrote:

> Hi Stefan,
>
> I would recommend looking into using a schema language (XML Schema,
> Relax NG) instead of a DTD.
> With DTD probably the best approach is to use parameter entities to
> define the content model for elements and the available attributes. You
> can look at DocBook 4 for an example of using parameter entities. Note
> that the next version of DocBook, DocBook 5 will provide a Relax NG
> schema. More, it should be possible to convert from schema to DTD so if
> you need to provide also a DTD then you will be able to do so. DocBook
> 5 for instance will provide also a DTD and an XML Schema.
>
> Best Regards,
> George
> ---------------------------------------------------------------------
> George Cristian Bina
> <oXygen/> XML Editor, Schema Editor and XSLT Editor/Debugger
> www.---.com
>
>
> stefan.rickfjord@g... wrote:
> > Hi,
> >
> > I am a newbie to programming using XML and I'm currently working on a
> > side-project which will house some database information in a XML-file.
> > I am writing a DTD to specify the XML-format, mostly for the purpose of
> > documenting the XML database.
> >
> > My issue is that I have some fields, e.g.
> > <!ELEMENT Vehicle ( Car? )>
> > <!ELEMENT Car ( Gasoline | Diesel )>
> > <!ELEMENT Gasoline EMPTY>
> > <!ELEMENT Diesel EMPTY>
> >
> > but I want to make sure that this database is extendable. I.e. after
> > using the database for a while in my application I want to be able to
> > add stuff that I come up with later on, e.g.
> > <!ELEMENT Motorcycle ( Sportbike | Harley )>
> > <!ELEMENT Sportbike EMPTY>
> > <!ELEMENT Harley EMPTY>
> >
> > I'd rather not add a lot of "Reserved"-elements in the DTD, as this is
> > not a nice solution. My own little idea is that i'm anyway able to add
> > items to the DTD further on since I both have the DTD of the XML and
> > the source of the application using it. Is this correct?
> >
> > I've looked around and found another way to do this and that is to
> > include the old DTD as an entity, is that the way to go?
> >
> > Please excuse my newbie-question, I just want to know if my way of
> > thinking is correct.
> > 
> > Thanks a lot for reading!