Issue 11. MNrepeat: Repeat M-N times

[Josh Lubell <lubell@cme.nist.gov>]

During the April 19 teleconference I took on an action item to find additional evidence of the popularity of min/max constraints in existing XML schemas. Here are some real-world examples, all of which use minOccurs and/or maxOccurs to represent cardinality constraints. I'm sure I could find more if the TC is still unconvinced that min/max would be a good idea for TREX version 1.

 

1. Geography Markup Language

http://www.ned.dem.csiro.au/XMML/gml2/

A LinearRing is defined by four or more coordinate tuples.

 

2. Extensible Provisioning Protocol Domain Name Mapping (IETF Internet Draft)

http://search.ietf.org/internet-drafts/draft-hollenbeck-epp-domain-01.txt

An EPP <update> command (whatever the heck *that* is) can contain up to 8 add/remove elements.

 

3. flightSchedule schema from Virgin Atlantic Airways

http://www.biztalk.org/library/view_object_details.asp?id=542 (you have to request a BizTalk userid and password to read this URL)

Flight instances have from 1 to 7 days of operation

 

I also found some examples with maxOccurs equal to 2. Although the need for min/max for the following is less compelling than for examples 1 through 3, I still think there would be some benefit.

 

4. XML Schema for Topic Maps

http://www.diffuse.org/TopicMaps/schema.html

An association between topics can have at most 2 prompts (textual clues to the user).

 

5. US Ballot Markup Language

http://schemas.soap-wrc.com/usbml/docs/ballotml.html

A ballot has to have 2 signatures.

 

6.XML Schema for GenCam (a standard for printed circuit board assemblies)

http://www.gencam.org/

A Test Connection connects 2 objects.

 

Regards,

Josh

Joshua Lubell, NIST
100 Bureau Drive, Stop 8263
Gaithersburg MD 20899-8263 USA
(301) 975-3563
lubell@nist.gov