Sorry the schema given below was wrong. Won't pass the validation.
here's the correct one:
  <xs:complexType name="formatComplexType">
    <xs:sequence>
      <xs:choice>
        <xs:element minOccurs="1" maxOccurs="1"
          name="formatDesignation" type="formatDesignationComplexType">
        </xs:element>
        <xs:element minOccurs="1" maxOccurs="1"
          name="formatRegistry" type="formatRegistryComplexType">
        </xs:element>
      </xs:choice>
      <xs:element minOccurs="0" maxOccurs="unbounded"
        name="formatRegistry" type="formatRegistryComplexType">
      </xs:element>
    </xs:sequence>
  </xs:complexType>

Thanks,

Zhiwu


On Mon, 2006-02-06 at 09:30, Zhiwu Xie wrote:
> Thanks a lot for the answer.
> 
> About the ambiguity introduced by multiple registry entries, IMHO that's
> the problem of the schema users. The schema users will have to make sure
> multiple registry entries point to the same format and no ambiguity is
> introduced. 
> 
> So the schema will need to be modified accordingly, to something like
> this:
> 
> <xs:complexType name="formatComplexType">
>   <xs:choice>
>     <xs:element minOccurs="1" maxOccurs="1"
>       name="formatDesignation" type="formatDesignationComplexType">
>     </xs:element>
>     <xs:element minOccurs="1" maxOccurs="unbounded"
>       name="formatRegistry" type="formatRegistryComplexType">
>     </xs:element>
>     <xs:sequence>
>       <xs:element minOccurs="1" maxOccurs="1"
>         name="formatDesignation" type="formatDesignationComplexType">
>       </xs:element>
>       <xs:element minOccurs="1" maxOccurs="unbounded"
>         name="formatRegistry" type="formatRegistryComplexType">
>       </xs:element>
>     </xs:sequence>
>   </xs:choice>
> </xs:complexType>
> 
> 
> Thanks,
> 
> Zhiwu Xie
> 
> Graduate Research Assistant
> Research Library
> Los Alamos National Lab
> 
> 
> On Mon, 2006-02-06 at 07:38, Priscilla Caplan wrote:
> > That's a good question.  I went back through committee minutes and found 
> > this entry:  "We should add in a note that if you are using a 
> > fileformatName, you don't need to also use a pointer into a registry; 
> > use one or the other (or both if you'd like)."  Thanks to Erin Rhodes, 
> > who was the best minute-taker ever.  The "both if you'd like" never made 
> > it into the data dictionary, but I can't find anything in subsequent 
> > minutes to indicate a change of mind.
> > 
> > So apparently there was no intent by PREMIS to make these elements 
> > mutually exclusive, and you can use both a format name and a pointer 
> > into a registry if you desire.
> > 
> > Regarding the ambiguity of multiple registries, yes, I can see this 
> > would be a problem.  We made the registry pointer repeatable because we 
> > envisioned there could be many different registries containing different 
> > types of information.  For example, one registry might have format 
> > specifications, while another might contain detailed environment 
> > information but no specifications.  You would indicate what kind of 
> > information you were getting from each registry by using the "role" 
> > element.  BUT, there would be nothing preventing you from pointing to 
> > two registries for the same information.  If there were multiple 
> > registries, it seems to me their content is more likely to be 
> > overlapping than globally unique.
> > 
> > Since we don't really have much experience with registries yet, we just 
> > have to make our best guesses.
> > 
> > p
> > 
> > Bronwyn Lee wrote:
> > > Re Zhiwu Xie's comment: "Just to clarify, this is one or the other, not
> > > one and/or the other, meaning I can't have both. Am I right?"
> > > 
> > > Would there be any reason to not allow both? If the formatRegistryKey
> > > contained the format name (and version) it would be OK not to have
> > > formatName as well, but if the formatRegistryKey was just a record
> > > number, it would be nice to 'see' the format name without having to go
> > > to the registry. If you allowed both, I suppose there could be ambiguity
> > > if the formatName didn't match what was in the registry entry - however
> > > even if you didn't allow both, ambiguity could occur, since
> > > formatRegistry is repeatable and the occurrences could potentially
> > > indicate different formats.
> > > 
> > > Bronwyn Lee
> > > Australian Partnership for Sustainable Repositories
> > > (http://www.apsr.edu.au)
> > > National Library of Australia
> > > Canberra ACT 2600 Australia
> > > 
> > >