Can we declare more than one sequence tags in a complex type?

Question

Hi all,
Can we use more than one <sequence> tags in the xml schema?
<xs:complexType name="Demo">
<xs:sequence minoccurs = "1" maxoccurs = "1">
</xs:sequence>
<xs:sequence minoccurs = "0" maxoccurs = "1">
</xs:sequence>
</xs:complexType>
If you observe the above sample xml there are two sequences in one complex type with different values for minoccurs and maxoccurs. Is this xml valid? why I need this is I have an
XML with lot of elements some of them should have minoccurs = "1" maxoccurs = "1" and some other should have the other combination of min and max attributes. I want to
declare it in the sequence rather than declaring beside each individual element. is that possible?
Thanks.

Answer 1

Hi,
Is this xml valid? No, a complexType expects only one child, but you can do this :
<xs:complexType name="Demo">
  <xs:sequence>
    <xs:sequence minOccurs = "1" maxOccurs = "1">
    </xs:sequence>
    <xs:sequence minOccurs = "0" maxOccurs = "1">
    </xs:sequence>
  </xs:sequence>
</xs:complexType>However...
XML with lot of elements some of them should have minoccurs = "1" maxoccurs = "1" and some other should have the other combination of min and max attributes.
I want to declare it in the sequence rather than declaring beside each individual element. is that possible?minOccurs and maxOccurs declared in the sequence apply to the sequence as a whole, not to its individual components.
For example :
<xs:schema xmlns:xs="http://www.w3.org/2001/XMLSchema">
     <xs:complexType name="Demo">
          <xs:sequence>
               <xs:sequence maxOccurs="1" minOccurs="1">
                    <xs:element name="test1" type="xs:string"/>
                    <xs:element name="test2" type="xs:string"/>
               </xs:sequence>
               <xs:sequence maxOccurs="1" minOccurs="0">
                    <xs:element name="test3" type="xs:string"/>
                    <xs:element name="test4" type="xs:string"/>
               </xs:sequence>
          </xs:sequence>
     </xs:complexType>
     <xs:element name="root" type="Demo"/>
</xs:schema>What you expect will work for the first sequence of elements (test1 and test2) but anyway minOccurs and maxOccurs for elements default to 1, so why bother wrapping them in a sequence?
If I understand what you want correctly, it won't work for the second sequence.
For instance, this will be valid :
<root>
  <test1/>
  <test2/>
  <test3/>
  <test4/>
</root>but this will not :
<root>
  <test1/>
  <test2/>
  <test3/>
</root>