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Re: modeling, validating and documenting an xml grammar

• To: Joe English <jenglish@f...>
• Subject: Re: modeling, validating and documenting an xml grammar
• From: "Chiusano Joseph" <chiusano_joseph@b...>
• Date: Wed, 18 Jun 2003 07:45:54 -0400
• Cc: xml-dev@l...
• Organization: BAH
• References: <AOEKKCOOGNDOAHCLNEIFKENKDOAA.mike@w...> <200306172155.h5HLth113469@d...>

<Quote>
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.
</Quote>

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.

Kind Regards,
Joe Chiusano
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
> 
>   jenglish@f...
> 
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• Follow-Ups:
  • Re: modeling, validating and documenting an xml grammar
    • From: "Rick Jelliffe" <ricko@a...>
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    • From: "Simon St.Laurent" <simonstl@s...>

• References:
  • RE: modeling, validating and documenting an xml grammar
    • From: "Mike Fitzgerald" <mike@w...>
  • Re: modeling, validating and documenting an xml grammar
    • From: Joe English <jenglish@f...>

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