- From: Michael Kay <mike@saxonica.com>
- Date: Wed, 30 Jan 2008 10:43:28 -0000
- To: "'Pete Cordell'" <petexmldev@codalogic.com>, "'Tsao, Scott'" <scott.tsao@boeing.com>
- Cc: <xmlschema-dev@w3.org>
> In fact, if you are just talking messages, there may be no > defined 'application' data model at all (at least not an XML > based one). Protocols such as VoIP and HTTP are generally > defined mainly in terms of the messages that flow between nodes. Sure (though VoIP and HTTP are lower down the stack: they are channels of communication rather than application message formats. Neither of them knows anything about business objects). I've certainly come across situations where people were struggling to define messages between two applications because they hadn't defined the common data model first. One application was using the term "retailer" to refer to a shop, the other was using it to refer to a chain of shops under common ownership, and untold confusion arose as a result. The other side of the coin is that I've seen people try to define the application data model as an XML Schema, and then wonder why their messages were so large - they were sending masses of data that the recipient didn't need, simply because the schema said it was mandatory. They hadn't separated data modelling from message design. Michael Kay http://www.saxonica.com/
Received on Wednesday, 30 January 2008 10:43:39 UTC