Re: on databinding and programming languages

Yves and others on the list:

 

Yves wrote

 

Also, choosing to remove constraints because it doesn't fit well with the 
type definition in some commonly used languages may impact people that 
want to use strong typed languages like ADA.

 

I agree with this statement; in fact, Ada is one of the language bindings I
would be interested in supporting. 

 

I have found constraints to be useful not just for matching types in Ada,
but also for ensuring data validity. I once worked on a medical application
where we were transferring data over a network connection using XML
messages. We used constraints in the XSD to ensure that the system was not
ingesting invalid data. That is, the receiver's SAX parser was validating
the messages against the XSD and discarding data that violated the
constraints. We could of course have just validated all the data in our C++
code, but it was faster to build our prototype just using all of the nice
features of XSD and the SAX parsing library. Changing constraints in XMLspy
was (IMO) a lot easier than fixing them in C++ code as no re-compiles etc.
were needed.

 

Anyway, I agree that constraints should be included.

 

 

Michael P. Card

Syracuse Research Corporation

(315) 452-8290

mcard@syrres.com