Is a collection of independent, unrestricted element definitions a"data

["Costello, Roger L." <costello@mitre.org>]

Hi Folks,

Suppose I create a data model (an XML Schema) that consists of a collection of independent, unrestricted definitions. The data model is to be used by communities that are quite different. Would you call the data model a "data exchange format"? Or would you call it something else?

Example: I declare an <Object> element that consists of an abstract <Value> element. I then declare a wide variety of elements that may substitute for <Value>:

- <House>
- <Aircraft>
- <Cellphone>
- <Book>

Notice that they are very different things.

Very different XML instance documents could be created from the data model: For sending to my realtor, I could create an instance that describes a house: 

<Object>
      <House>ranch style, brick</House>
</Object>

For communicating with an officer at a military base I could create an instance that specifies an aircraft: 

<Object>
      <Aircraft>
            <Type>B-52H</Type>
            <MaxAirspeed>650 MPH</MaxAirspeed>
      </Aircraft>
</Object>

And so forth. 

Clearly the data model contains items that are very different and are intended for different audiences.

The data model is too nebulous and too open-ended to be called a data exchange format (I think). For me, a data exchange format is something that specifies precisely the type of data that will be exchanged: If I am exchanging data with my realtor, a data exchange format would specify that XML instances will contain <House> data and not, say, data about an <Aircraft>. 

It seems to me that my unconstrained data model is not a data exchange format. But what is it? What would you call a collection of independent, unrestricted element definitions?

/Roger