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What are the real-world use cases of minOccurs and maxOccurs?
In my experience, occurrence constraints specifying anything
other than zero, one, or many are almost always an indication
of a bad design decision somewhere in the system.
Off the top of my head: A student can enroll in no more than X courses
per semester - so the occurrences of Course information for a student
would be limited to X occurrences.
Booz | Allen | Hamilton
Joe English wrote:
> Mike Fitzgerald wrote:
> > Bob Foster wrote:
> > > From: "Mike Fitzgerald"
> > > Also, RELAX NG lacks the precise occurrence restraints of XML
> > > Schema that is, no minOccurs/maxOccurs. RNG supports only the common RE
> > > or DTD constraints ? * + as <optional>, <zeroOrMore>, and <oneOrMore>.
> > >
> > > Yes, but that's just shorthand; it doesn't add any additional capability.
> > In some respects, it is shorthand, e.g.:
> > ? is <optional> is minOccurs="0" maxOccurs="1"
> > but you can't say a min of 9 occurrences with a max of 12 in RELAX NG; you
> > can in XML Schema with minOccurs="9"/maxOccurs="12". However, M-N
> > constraints are on the official docket for RELAX NG as a separate spec.
> What are the real-world use cases of minOccurs and maxOccurs?
> In my experience, occurrence constraints specifying anything
> other than zero, one, or many are almost always an indication
> of a bad design decision somewhere in the system.
> (Or maybe that *is* the use case? To be able to accurately
> describe badly normalized legacy RDBMSs and other such things?)
> --Joe English
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