After the XSD file defines a TargetNameSpace, its internal defined elements, properties, types, etc. are the targetNamespace, their own or external XSD files use these elements, attributes, etc. must be found in the defined targetNamespace:
For example: The following XSD file has the error, even in an XSD, you must also find a reuse from the defined namespace:
In the above code, the complex type STU cannot be found because you define a namespace AAA, which exists in AAA, so modifying the code as follows:
If it is not to be built with reuse, only for external use, only the targetnamespace can be defined, and you can use it without specifying an alias.
