Complex Type Elements - Mixed Attribute

[Aruna]

In complex type elements what is the purpose of mixed attribute?<xs:element name="letter" type="lettertype"/><xs:complexType name="lettertype" mixed="true"> <xs:sequence> <xs:element name="name" type="xs:string"/> <xs:element name="orderid" type="xs:positiveInteger"/> <xs:element name="shipdate" type="xs:date"/> </xs:sequence></xs:complexType>Does the mixed attribute specify that any datatype can be used. Here i can see that the datatype of name is hardcoded as string and that of orderid is hardcoded as positiveInteger. What's the purpose of mixed attribute in complex type elements?