[xsd] restricting complex type

[np2k]

hi all. i'm a newbie in xsd world. my question regards the complex type.

let's suppose that we have this definition:

<xs:complexType name = "employee">
  <xs:sequence>
     <xs:element name="name" type="xs:string"/>
     <xs:element name="surname" type="xs:string"/>
     <xs:element name="nation" type="xs:string"/>
  </xs:sequence>
</xs:complexType>

well now i'll restrict this complex type creating a new one "itaemployee", which contains a fixed value for the tag "nation" (=italy)

<xs:complexType name = "itaemployee">
  <xs:complexContent>
    <xs:restriction base = "employee">
     <xs:sequence>
      <xs:element name="name" type="xs:string"/>
      <xs:element name="surname" type="xs:string"/>
      <xs:element name="nation" type="xs:string" fixed="italy"/>
     </xs:sequence>
    </xs:restriction>
   <xs:complexContent>
<xs:complexType>

now, my question: why i should restrict the type employee to have itaemployee? I could also write:

<xs:complexType name = "itaemployee">
     <xs:sequence>
      <xs:element name="name" type="xs:string"/>
      <xs:element name="surname" type="xs:string"/>
      <xs:element name="nation" type="xs:string" fixed="italy"/>
     </xs:sequence>
<xs:complexType>

having a type called itaemployee...
what is the benefit using the restriction of the complex type?

help me to understand, please!

[rpgfan3233]

The benefit in your example is rather questionable. However, when you have a number of elements that are in a category of sorts, such as when you buy something at a store, including employee discounts:

<xs:complexType name="item.type">
  <xs:sequence>
    <xs:element name="name" type="xs:string"/>
    <xs:element name="price" type="xs:decimal"/>
    <xs:element name="discount" type="xs:decimal" minOccurs="0"
                default="0.0"/>
    <xs:element name="employee-discount" type="xs:decimal" minOccurs="0"
                default="0.0"/>
  </xs:sequence>
</xs:complexType>

<xs:complexType name="employee-item.type">
  <xs:complexContent>
    <xs:restriction base="item.type">
      <xs:sequence>
        <xs:element name="name" type="xs:string"/>
        <xs:element name="price" type="xs:decimal"/>
        <xs:element name="discount" type="xs:decimal" minOccurs="0"
                    default="0.0"/>
        <xs:element name="employee-discount" type="xs:decimal"
                    fixed="0.15"/>
      </xs:sequence>
    </xs:restriction>
  </xs:complexContent>
</xs:complexType>

Then instead of using the following:

<item>
  <name>Example</name>
  <price>9.99</price>
</item>

<item>
  <name>Example</name>
  <price>9.99</price>
  <employee-discount>0.15</employee-discount>
</item>

You could use this instead:

<item>
  <name>Example</name>
  <price>9.99</price>
</item>

<employee-item>
  <name>Example</name>
  <price>9.99</price>
</employee-item>

Again, a dumb example, but when you consider adding more elements (e.g. instead of "price", you have "price" and "profit"), you might find it useful. Honestly, I don't typically see using restrictions in this way beneficial. Extensions are more useful for this sort of thing...adding elements and groups rather than restricting elements. I don't find much use for restrictions in complex content. Enumerations in simple content and simple types are what I use them for most commonly.

[np2k]

yes, i see...
but I would have been able to write like this:

<xs:complexType name="employee-item.type">
      <xs:sequence>
        <xs:element name="name" type="xs:string"/>
        <xs:element name="price" type="xs:decimal"/>
        <xs:element name="discount" type="xs:decimal" minOccurs="0"
                    default="0.0"/>
        <xs:element name="employee-discount" type="xs:decimal"
                    fixed="0.15"/>
  </xs:complexContent>
</xs:complexType>

id est: defining a new complex type called "employee-item.type"...the usage is the same, but exists the restriction of complex type...so my question is: what is the benefit of this restriction? i was thinking, maybe exists an object-oriented benefit that i cannot see in this moment...

help help

[np2k]

can someone help me?