Conditional required elements in an XSD

Question

I have a requirement for an xml schema which accepts either a request with the customer or with the customer id. If the customer Id is 0 then we need the customer data, if

Answer 1

This is possible in XSD 1.1; below is a simplified example, which assumes MainApplicant and WhereSigned are mandatory when CustomerId is equal to zero.

Minimum valid XML, when CustomerId is zero:

    UserID1
    asodasqZX==
    0
    
    

When CustomerId is non-zero, then this is the minimum XML:

    UserID1
    asodasqZX==
    1

The conditional can be easily controlled (see the @test expression); add regular XSD constraints as needed (e.g. if your CustomerId needs to be greater than or equal to zero, then make it nonNegativeInteger, etc.)