Biztalk mapper altering nodes order - biztalk

Question

I need to map document X to document Y, being both quite similar. X has the following [fragment of] XSD:
<xsd:complexType>
<xsd:sequence>
<xsd:choice minOccurs="3" maxOccurs="unbounded">
<xsd:element maxOccurs="unbounded" ref="A" />
<xsd:element maxOccurs="unbounded" ref="B" />
<xsd:element maxOccurs="unbounded" ref="C" />
<xsd:element minOccurs="0" maxOccurs="unbounded" ref="D"/>
</xsd:choice>
</xsd:sequence>
</xsd:complexType>
Y has the same elements (A,B,C), but they're not within a sequence.
My problem arises when I test the map with the following input:
<doc-X>
<A>...</A>
<B>...</B>
<C>...</C>
<D>...</D>
<C>...</C>
<D>...</D>
</doc-X>
I get something like this:
<doc-Y>
<A>...</A>
<B>...</B>
<C>...</C>
<C>...</C>
<D>...</D>
<D>...</D>
</doc-Y>
I don't understand why is this happening, since I just map each element with its corresponding pair on the other schema.
EDIT : I've tried putting the property PreserveSequenceOrder to "Yes", but that hasn't worked

Answer 1

XSD on its own does not guarantee that sibling elements will appear in any given order. From what you've described, it sounds like the output is perfectly valid according to its schema. Are you actually getting a failure in your test map?
Is there any way you can post the complete schema and document instances?

Answer 2

You are getting that output because, Map always look for output document ( Document Y) Connections from top elment to bottom element. So in your case it will execute first elment A ( in Document Y) Links, afterthat B, after that C.
Try to modify the output doucment( Document Y) xsd to sth like this
<xsd:complexType>
<xsd:sequence>
<xsd:choice minOccurs="3" maxOccurs="unbounded">
<xsd:element maxOccurs="unbounded" ref="D" />
<xsd:element maxOccurs="unbounded" ref="C" />
<xsd:element maxOccurs="unbounded" ref="B" />
<xsd:element minOccurs="0" maxOccurs="unbounded" ref="A"/>
</xsd:choice>
</xsd:sequence>
</xsd:complexType>
You will see the difference.....