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> I had somewhere the same problem, i.e. the (painful :-) dilemma: > > a) either fine control of the number of occurrences (obtained via > <sequence>); > b) or unconstrained order (obtained via <choice maxOccurs="unbounded">). > > Maybe we should suggest W3C (for the XSD 1.1) the "natural" extension, Or even more elegant: generalising a bit the <all> construct, like: <all> <element name="e(p)" minOccurs="n(p)" maxOccurs="m(p)">... </element> ... <element name="e(q)" minOccurs="n(q)" maxOccurs="m(q)">... </element> </all> where n(i) >= 0 and m(i) >= n(i). Feasable ? Dan > something like: > > <choice minOccurs="x" maxOccurs="y"> > <element name="e(p)" minOccurs="n(p)" maxOccurs="m(p)">... </element> > ... > <element name="e(q)" minOccurs="n(q)" maxOccurs="m(q)">... </element> > </choice> > > where the elements are allowed in any order, but WITH a constrained number of > occurrences. > > In this case, x and y are imposed (i.e. they could disappear ?): > > x = sum (n(i), i = p..q) > y = sum (m(j), j = p.. q) > > > What do you think ? > > Dan > > ----------------------------------------------------------------------- > Dan Matei, director > CIMEC - Institutul de Memorie Culturala [Institute for Cultural Memory] > Piata Presei Libere nr. 1, CP 33-90 > 013701 Bucuresti [Bucharest], Romania > tel. (+40-21) 317 90 72; fax (+40-21) 317 90 64 > www.cimec.ro > > > -----Original Message----- > From: Joe Altimus <[log in to unmask]> > To: [log in to unmask] > Date: Fri, 8 Aug 2008 14:53:00 -0700 > Subject: Re: [MODS] schema use of xsd:sequence to define children of the > cartographics element > > > OK, I think I get it. There is no good reason for rigidly ordering these > > elements, we've just run into a limitation of the XML Schema standard. > > > > On Fri, Aug 1, 2008 at 6:55 AM, Ray Denenberg, Library of Congress < > > [log in to unmask]> wrote: > > > > > <cartographics> is defined as xsd:sequence because <scale> and > > > <projection> > > > are not repeatable, but <coordinates> is repeatable. > > > > > > <all> requires that each element occur zero or one time and would not > allow > > > multiple <coordinates> elements. > > > > > > <choice maxOccurs="unbounded"> (which MODS uses in cases without such > > > constraints) would not constrain <scale> and <projection> to maximum one > > > occurence. > > > > > > (Contrast this for example with <subject> ........ > > > > > > <choice maxOccurs="unbounded"> > > > <element name="topic"/> > > > <element name="geographic"/> > > > <element name="temporal"/> > > > <element name="titleInfo"/> > > > > > > etc. > > > > > > </choice> > > > > > > etc. > > > > > > .....any of these subject categories may occur any number of times, > > > including zero, and the whole set may occur in any order.) > > > > > > > > > ----- Original Message ----- > > > From: "Joe Altimus" <[log in to unmask]> > > > To: <[log in to unmask]> > > > Sent: Thursday, July 31, 2008 5:30 PM > > > Subject: [MODS] schema use of xsd:sequence to define children of the > > > cartographics element > > > > > > > > > I notice that the MODS schema uses xsd:sequence to define the children > > > of the cartographics element: > > > > > > <xsd:sequence> > > > <xsd:element name="scale" minOccurs="0" type="xsd:string"/> > > > <xsd:element name="projection" minOccurs="0" > > > type="xsd:string"/> > > > <xsd:element name="coordinates" minOccurs="0" > > > maxOccurs="unbounded" type="xsd:string"/> > > > </xsd:sequence> > > > > > > However, an example of <cartographics> in the MODS User Guidelines > > > does not conform to the schema: > > > > > > <subject> > > > <cartographics> > > > <coordinates>E 72°--E 148°/N 13°--N 18°</coordinates> > > > <scale>1:22,000,000</scale> > > > <projection>Conic proj</projection> > > > </cartographics> > > > </subject> > > > > > > so I wonder if the example is wrong or the Schema (xsd:all instead of > > > xsd:sequence)? Is there a strong reason why the children should occur > > > in a rigid order in this case? > > > > > > Joe Altimus > > > Arizona State University Libraries > > >