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XSD Conditional Elements

I need to make some elements required based on the value of another element.

<xs:element name="LoanType" type="xs:string" />
If LoanType is Adjustable then
<xs:element name="Margin" type="xs:int" />
else
<xs:element name="Margin" type="xs:int" minOccurs="0' />

Thanks in advance.

Gertone (Geert Bormans)

You can't achieve this by simply XSD.
What you are asking for is a co-occurence constraint, a type of constraint that can not be modelled by XSD schema.
You basically have three options
- have a second schema that uses schematron constraints (http://www.schematron.com/)
- use an XSD parser that allows embedded schematron rules (this would be the approach I would use)
- use an XSD parser that understands XSD 1.1, a new schema evolution that has "assert", very similar to schematron assertions

CodeMarx

ASKER

How about applying a XLST to the XML document first?

ASKER CERTIFIED SOLUTION

Gertone (Geert Bormans)

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BigRat

One defines a complecType called LoansType, which is a choice of various loan types (elements). One such element is called AdjustableLoanType which then can have Margin as either a sub-element or an attribute.

Generally if you have an enumeration which causes structural differences then you should enumerate the structures rather than use a scalar and overload the structure.