[Nml-wg] Review of the XSD schema

Wed Jan 16 05:57:33 EST 2013

W dniu 2012-12-28 02:34, Freek Dijkstra pisze:
>
> General questions and remarks:
> ------------------------------
>
> * Where does it specify that all NML descriptions should start with
> nml:Topology as the root element?

It's not specified. No need.

>
> * In the current schema, the order of child elements is very strict --
> it is a sequence of elements in particular order. For example, a
> relation element MUST occur before a Location element. If relation
> occurs after a Location, the document is invalid.
>
> Here is an excerpt for the schema:
>
>>    <xs:complexType name="NetworkObject">
>>      <xs:sequence>
>>        <xs:element  name="name"       type="xs:string"          minOccurs="0"  maxOccurs="1"/>
>>        <xs:element  name="relation"   type="nml:RelationType"   minOccurs="0" />
>>        <xs:element  name="Location"   type="nml:LocationType"   minOccurs="0"  maxOccurs="1"/>
>>        <xs:element  name="parameter"  type="nml:ParameterType"  minOccurs="0"/>
>>        <!-- .... -->
>>      </xs:sequence>
>>      <!-- .... -->
>>    </xs:complexType>
> Instead, I would suggest to use xs:all:
>
>>    <xs:complexType name="NetworkObject">
>>      <xs:all>
>>        <xs:element  name="name"       type="xs:string"          minOccurs="0"  maxOccurs="1"/>
>>        <xs:element  name="relation"   type="nml:RelationType"   minOccurs="0" />
>>        <xs:element  name="Location"   type="nml:LocationType"   minOccurs="0"  maxOccurs="1"/>
>>        <xs:element  name="parameter"  type="nml:ParameterType"  minOccurs="0"/>
>>        <!-- .... -->
>>      </xs:all>
>>      <!-- .... -->
>>    </xs:complexType>

In theory the use of xs:all is allowed inside xs.complexType but when I 
run validation for it in this case (based on Xerces) it gets crazy:

Error at (file nmlbase.xsd, line 149, char 47): all compositor that is 
part of a complex type definition must constitute the entire content of 
the definition

Error at (file nmlbase.xsd, line 196, char 47): all compositor that is 
part of a complex type definition must constitute the entire content of 
the definition

Error at (file nmlbase.xsd, line 107, char 47): all compositor that is 
part of a complex type definition must constitute the entire content of 
the definition

Error at (file nmlbase.xsd, line 235, char 46): all compositor that is 
part of a complex type definition must constitute the entire content of 
the definition

Error at (file nmlbase.xsd, line 287, char 47): all compositor that is 
part of a complex type definition must constitute the entire content of 
the definition

Error at (file nmlbase.xsd, line 323, char 47): all compositor that is 
part of a complex type definition must constitute the entire content of 
the definition

Error at (file nmlbase.xsd, line 359, char 47): all compositor that is 
part of a complex type definition must constitute the entire content of 
the definition

Error at (file nmlbase.xsd, line 416, char 47): all compositor that is 
part of a complex type definition must constitute the entire content of 
the definition

Error at (file nmlbase.xsd, line 460, char 47): all compositor that is 
part of a complex type definition must constitute the entire content of 
the definition

Error at (file nmlbase.xsd, line 494, char 47): all compositor that is 
part of a complex type definition must constitute the entire content of 
the definition

Error at (file nmlbase.xsd, line 523, char 47): all compositor that is 
part of a complex type definition must constitute the entire content of 
the definition

Error at (file stdin, line 7, char 45): attribute 'id' is not declared 
for element 'Topology'

Error at (file stdin, line 7, char 45): attribute 'version' is not 
declared for element 'Topology'

Error at (file stdin, line 17, char 77): attribute 'id' is not declared 
for element 'Link'

Error at (file stdin, line 17, char 77): attribute 'encoding' is not 
declared for element 'Link'

Error at (file stdin, line 21, char 57): attribute 'id' is not declared 
for element 'Node'

Error at (file stdin, line 37, char 69): attribute 'id' is not declared 
for element 'Topology'

Error at (file stdin, line 39, char 77): attribute 'id' is not declared 
for element 'BidirectionalPort'

Error at (file stdin, line 40, char 71): attribute 'id' is not declared 
for element 'Port'

Error at (file stdin, line 41, char 70): attribute 'id' is not declared 
for element 'Port'

It does not like the structure:

   <xs:complexType name="...">
     <xs:complexContent>
       <xs:extension  base="nml:NetworkObject">

Besides xs:all seems to be very limited. It can not contain xs:group, 
xs:choice, xs:sequence.

> * I don't really understand how you are trying to deal with implicit and
> explicit relations.
> This seems at first very powerful (meaning: either use implicit or
> explicit):
>
>>        <xs:choice>
>>          <xs:element  name="lifetime"     type="nml:LifeTimeType"     minOccurs="0"  maxOccurs="1"/>
>>          <xs:element  name="existDuring"  type="nml:ExistDuringType"  minOccurs="0"  maxOccurs="1"/>
>>        </xs:choice>
> In fact there are four ways to represent implicit relations:
>
> 1.
>
> <nml:Node id="...">
>    <nml:name>My Device</nml:name>
>    <nml:Location>
>      <nml:name>Somewhere</nml:name>
>    </nml:Location>
> </nml:Node>
>
> 2.
>
> <nml:Node id="...">
>    <nml:name>My Device</nml:name>
>    <nml:Relation type="http:....nml/base#locatedAt">
>      <nml:Location>
>        <nml:name>Somewhere</nml:name>
>      </nml:Location>
>    </nml:Relation>
> </nml:Node>
>
> 3.
>
> <nml:Node id="...">
>    <nml:name>My Device</nml:name>
>    <nml:Location id="..." />
> </nml:Node>
> <nml:Location id="...">
>    <nml:name>Somewhere</nml:name>
> </nml:Location>
>
> 4.
>
> <nml:Node id="...">
>    <nml:name>My Device</nml:name>
>    <nml:Relation type="http:....nml/base#locatedAt">
>      <nml:Location id="..." />
>    </nml:Relation>
> </nml:Node>
> <nml:Location id="...">
>    <nml:name>Somewhere</nml:name>
> </nml:Location>
>
> Currently, for Location/locatedAt only the form 1 seems allowed.
> For LifeTime/existDuring only forms 1 and 3 seem allowed.
>
> Is this on purpose? (I presume it is on purpose that the explicit
> variants are not listed, but that the missing form #3 for Location is a
> omission.)
>
> * To iterate on existsDuring: It seems that the described form it even
> slightly different:
>
> <nml:Node id="...">
>    <nml:name>My Device</nml:name>
>    <nml:existDuring idRef="..." />
> </nml:Node>
>
> (thus without the <nml:LifeTime> wrapper)

I updated Relations. Now there is clear distinction between implicit and 
explicit ones.

>
> Is that interpretation correct?
>
> * The RelationType lists all possible relation URIs as values for the
> type attribute. Is it permitted to use a URI not listed here? Thus, is
> is possible to define a new relation in nml-experimental, without
> changing nml-base?

Experimental relations I propose to put in a separate namespace. This 
should work.

>
> Specific remarks:
> -----------------
>
>>      <xs:attribute  name="idRef"    type="xs:anyURI"        use="optional"/>
> Remove line 32, as idRef is no longer used:

I keep idRef as we agreed to still support it (as an option; correct me 
if I'm wrong).

(updated version of the xsd schema is already uploaded in the repo)

Roman