[XML-DEV Mailing List Archive Home] [By Thread] [By Date] [Recent Entries] [Reply To This Message] Re: Why XML data typing is hard (was Re: Internal subset equivalent in n
<david@m...> writes: > Imagine that someone sent an expensive XML-based system from North > America to Norway, and you discovered that the system constrained > phone numbers > XML-based system from Norway to Beijing, and it constrained city > names to contain only Roman letters I see the problem, but that constraint is IMHO an indication that you somehow has encountered an area the system is unable to deal with. And very probably, you need to change other components of your system as well. Catching illegal values early on - in validation of the document - instead of relying on some obscure run-time error in some program, is a *feature*. One occasion I've run into, was when I needed sort keys for a list of records. Unfortunately, the data quality was not very good, and there were a lot of characters without defined sort semantics stuck in the sort field. I had, in effect, to write a small tool that parsed the data, and came up with the illegal keys. If content constraints were supported in the DTD and validator, I could have thrown the DTD at my customers and said that this is what I accept, and they would be free to use whatever tools they chose to verify that what they send me is valid. > but coming up with data-type constraints that both useful and > generalised enough for all XML users across all of the major Locales > and all of the Unicode character repetoire is *very* difficult. Only slightly more difficult than coming up with the DTD, IMHO, and certainly a lot less difficult than ensuring that your processing environment correctly deals with all ``major Locales'' and Unicode byzantinery and all. ~kzm -- If I haven't seen further, it is by standing in the footprints of giants xml-dev: A list for W3C XML Developers. To post, mailto:xml-dev@i... Archived as: http://www.lists.ic.ac.uk/hypermail/xml-dev/ To (un)subscribe, mailto:majordomo@i... the following message; (un)subscribe xml-dev To subscribe to the digests, mailto:majordomo@i... the following message; subscribe xml-dev-digest List coordinator, Henry Rzepa (mailto:rzepa@i...)
|
PURCHASE STYLUS STUDIO ONLINE TODAY!Purchasing Stylus Studio from our online shop is Easy, Secure and Value Priced! Download The World's Best XML IDE!Accelerate XML development with our award-winning XML IDE - Download a free trial today! Subscribe in XML format
|