Re: complexType derivation method

thanks for your explanations, unfortunatly I have some other doubts ; - ( :

1.    when i create a new complexType with complexContent by Restriction, can i modify the value of {min occurs} and/or {max occurs} of the model group schema components( i.e. <all> , <choice>, <sequence>)?

    
    <xs:complexType name="baseType">

          <xs:sequence minOccurs="2" maxOccurs="unbounded">

               ...

          </xs:sequence>

     </xs:complexType>

     

     <xs:complexType name="restrictedType">

          <xs:complexContent>

               <xs:restriction base="baseType">

                    <xs:sequence minOccurs="3" maxOccurs="12">

                         ...

                    </xs:sequence>

               </xs:restriction>

                    

          </xs:complexContent>

     </xs:complexType> 



2. extending a complextype using a complexContent:
    a.    can I extend an <all> with another <all> ? and with a <sequence> or with a <choice> ?
    b.    can I extend a <choice> with another <choice>? and with a <sequence > or with an <all> ?
    c.    can i extend a <sequence> with an <all> or with a <choice>?

3.    I do not understand the meaning of the following sentence from XML Schema Part 1: Structures 3.9.6 Constraints on Particle Schema Components:
    
Schema Component Constraint: Particle Valid (Extension) 

[Definition:]  For a particle (call it E, for extension) to be a valid extension of another particle (call it B, for base) one of the following must be true: 
1 They are the same particle. 
2 E's {min occurs}={max occurs}=1 and its {term} is a sequence group whose {particles}' first member is a particle all of whose properties, recursively, are identical to those of B, with the exception of {annotation} properties. 

someone may explain to me, with an example, when this constraint is applied...and if it is related with my first question.

thanks for the help,

andrea boriero mailto:aboriero@elet.polimi.it