RE: Constraint Specifications in XML Schemas

The schema you are trying to describe does not seem beyond the abilities of xs:key and xs:keyref. However it is definitely beyond the abilities of RELAX NG since I believe key/keyref was removed from the language. 

 -----Original Message----- 
 From: Alexandre Martins [mailto:alex.martins@netc.pt] 
 Sent: Fri 10/25/2002 2:52 PM 
 To: xmlschema-dev@w3.org 
 Cc: 
 Subject: Constraint Specifications in XML Schemas
 
 



 Hi!
 
 I've been trying to write a XML vocabulary to describe a relational database
 schema, for example:
 
 <DataBase id="teste" url="jdbc:mysql://localhost/teste" user="xano"
 passwd="xpto" driver="com.mysql.jdbc.Driver"
 xmlns:xsi="http://www.w3.org/2001/XMLSchema-instance"
 xsi:noNamespaceSchemaLocation="bd-v2.xsd">
 
   <Table id="Film">
     <Field id="idFilm" type="INTEGER">Film Number</Field>
     <Field id="title" type="VARCHAR" size="40">Title</Field>
     <Field id="year" type="INTEGER">Year</Field>
     <PrimaryKey>
       <KeyField fieldId="idFilm"/>
     </PrimaryKey>
   </Table>
   <Table id="Actor">
     <Field id="idActor" type="INTEGER">Actor Number</Field>
     <Field id="name" type="VARCHAR" size="25">Name</Field>
     <Field id="birthDate" type="DATE">Birthdate</Field>
     <PrimaryKey>
       <KeyField fieldId="idActor"/>
     </PrimaryKey>
   </Table>
   <Table id="FilmActor">
     <Field id="idFilm" type="INTEGER">Film Number</Field>
     <Field id="idActor" type="INTEGER">Actor Number</Field>
     <Field id="character" type="VARCHAR" size="20">Character</Field>
     <PrimaryKey>
       <KeyField fieldId="idFilm"/>
       <KeyField fieldId="idActor"/>
     </PrimaryKey>
     <ForeignKey>
       <FieldRef fieldId="idFilm"/>
       <ForeignTable tableId="Film">
         <ForeignField fieldId="idFilm"/>
       </ForeignTable>
     </ForeignKey>
     <ForeignKey>
       <FieldRef fieldId="idActor"/>
       <ForeignTable tableId="Actor">
         <ForeignField fieldId="idActor"/>
       </ForeignTable>
     </ForeignKey>
   </Table>
 </DataBase>
 
 In order to validate certain constraints related with the relational model
 rules, I've been developing a XML Schema.
 But I've not been able to write a XML Schema constraint to guarantee
 that a ForeignKey element content must be a PrimaryKey on the other table
 (i've trying with key and keyref).
 Is it possible to write this using XML Schema or must I use Relax NG??
 
 Thanks,
 Alexandre Martins
 
 
 
 
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Received on Friday, 25 October 2002 19:14:12 UTC