Document id reference desn't work for impex - sap

Question

I have a problem with impex which contains document id reference.
From docs:
"Especially for importing partOf item values it is necessary to reference these items by means other than the usual unique column technique because partOf items often do not provide a unique key but only hold their enclosing parent as foreign key."
Items from *items.xml (only the most important parts)
<itemtype code="A" autocreate="true" generate="true" abstract="true"/>
<itemtype code="B" autocreate="true" generate="true" extends="A">
<deployment table="btable" typecode="20115" />
<attributes>
<attribute qualifier="code" type="java.lang.Integer" autocreate="true" generate="true">
<persistence type="property"/>
<modifiers optional="false"/>
</attribute>
</attributes>
</itemtype>
<itemtype code="C" autocreate="true" generate="true">
<deployment table="ctable" typecode="20117" />
<attributes>
<attribute qualifier="code" type="java.lang.String" autocreate="true" generate="true">
<persistence type="property"/>
<modifiers optional="false" unique="true"/>
</attribute>
<attribute qualifier="test" type="A" autocreate="true" generate="true">
<persistence type="property"/>
<modifiers optional="false" partof="true"/>
</attribute>
</attributes>
</itemtype>
Impex code:
INSERT B;code;&docIdRef
;1;docId
INSERT_UPDATE C;code[unique=true];test(&docIdRef)
;uniqueCode;docId
Error message:
cannot create C with values ItemAttributeMap[ registry: null, type: <null>, (...) due to [de.hybris.platform.servicelayer.interceptor.impl.MandatoryAttributesValidator#3b777877]:missing values for [test] in model C
When I removed 'partof' modifier from 'test' attribute (C class) everything worked fine.
I wonder how impex should looks like if i want to keep 'partof' modifier.

Answer 1

When you use partOf you must reference the partOf using the owner.
So it does :
INSERT B;owner(C.code);&docIdRef
;uniqueCode;docId
INSERT_UPDATE C;code[unique=true];test(&docIdRef)
;uniqueCode;docId
You don't need to assign B an identifier, you just need to reference the owner.

Answer 2

If you know for sure that your data is correct you can use [forceWrite=true] modifier or legacy mode to skip service layer validation.
You should also make sure that this configuration is what you really need. Setting either optional to true or partOf to false or providing default value should fix the issue as well.

Answer 3

Since you have mentioned partof="true" you can not assign a reference of type A. You can only create a new entity.
Check the OOTB AbstractOrder2AbstractOrderEntry relationship, they have mentioned partof="true" for AbstractOrderEntry means you can't reference any other AbstractOrderEntry to Order. You can always create new entry.
Have a look at HMC site as well
You can see here there is no + Add Entry button available here. The reciprocal can be possible.