Re: [xml-dev] What techniques do you employ to ensure that your datais p

[Michael Kay <mike@saxonica.com>]

On 24/09/2012 17:12, Costello, Roger L. wrote:
> Hi Folks,
>
> How carefully do you specify your data? Is it free from ambiguity and misinterpretation?
>
>
Data is *never* free from ambiguity and misinterpretation, however 
careful you are: any more than English prose is ever unambiguous.

Being too careful can make things worse, because the longer and more 
formal the spec, the fewer people will read it.

And being too careful can make systems too rigid, preventing people from 
sharing the data that they want to make available.

Just ask two TV people to agree what they mean by a "channel", or two 
airline people what they mean by a "flight", or two software people to 
agree what they mean by a "bug". The fact is that in everyday 
conversation we use fuzzy terms all the time.

Of course, we've all heard of systems problems caused by failure to 
agree these definitions. My favourite anecdote is a lottery system in 
which the word "retailer" (and the retailer ID) was used variously to 
describe the premises on which tickets were sold, and the company that 
owned or leased those premises; and "terminal" (and terminal ID) was 
used variously to describe the physical piece of equipment in the shop, 
and the network endpoint to which it was plugged in. It all worked well 
so long as there was an unchanging one-to-one relationship between these 
objects. But this particular system was astoundingly successful in that 
it was built and went live within about six months, and once it did so, 
there was plenty of cashflow available to fix the problems.

Michael Kay
Saxonica