Xsd extension question

Question

Hello, I have a question about the extension of complex Types by xsd.
Can I use polymorphism with the extension of complex Types.
By example, I define a xml schema
<?xml version="1.0" encoding="UTF-8"?>
<xsd:schema xmlns:xsd="http://www.w3.org/2000/10/XMLSchema">
<xsd:element name="basic" type="basic">
<xsd:annotation>
<xsd:documentation>Comment describing your root element</xsd:documentation>
</xsd:annotation>
</xsd:element>
<xsd:complexType name="basic">
<xsd:sequence>
<xsd:element name="basicElement" type="xsd:string"/>
</xsd:sequence>
</xsd:complexType>
<xsd:complexType name="derivedBasic">
<xsd:complexContent>
<xsd:extension base="basic">
<xsd:sequence>
<xsd:element name="derivedElement" type="xsd:integer"/>
</xsd:sequence>
</xsd:extension>
</xsd:complexContent>
</xsd:complexType>
</xsd:schema>
Then my question is, can i use in an xml document which depends on the xml schema the complexType derivedBasic when a basic type is required. (Perhaps i can use a typecast or something).
I need this, because i want to make a xsd representation of an uml model and want to check dataexchange based on xml.
Thanks for your help
Andreas

Answer 1

If it was me I would post such questions in the XML forum.
If I understand the question it is not possible.
In general you cannot describe all possible data validation using only an XSD.