Add relations to dataset dynamically in Progress OpenEdge

I would like to create a dataset that only contains the temp-tables, and where the relations will be defined later.

When I define the relations in the dataset everything works fine

DEF TEMP-TABLE ttParent NO-UNDO
FIELD pKey AS INT
FIELD parentName AS CHAR.

DEF TEMP-TABLE ttChild NO-UNDO
FIELD iParent AS INT XML-NODE-TYPE "HIDDEN"
FIELD childName AS CHAR.

DEF DATASET dsMyDataset
FOR ttParent, ttChild

DATA-RELATION Parent_Child FOR ttParent, ttChild
RELATION-FIELDS(pKey, iParent)
NESTED FOREIGN-KEY-HIDDEN.

CREATE ttParent.
ASSIGN
ttParent.pKey = 1
ttParent.parentName = "Parent".

CREATE ttChild.
ASSIGN
ttChild.iParent = ttParent.pKey
ttChild.childName = "Child".

CREATE ttChild.
ASSIGN
ttChild.iParent = ttParent.pKey
ttChild.childName = "Child2".

DATASET dsMyDataset:WRITE-XML("FILE", "C:/temp/testDs.xml").


This creates the following XML as expected:

<?xml version="1.0"?>
<dsMyDataset xmlns:xsi="http://www.w3.org/2001/XMLSchema-instance">
<ttParent>
<pKey>1</pKey>
<parentName>Parent</parentName>
<ttChild>
<childName>Child</childName>
</ttChild>
<ttChild>
<childName>Child2</childName>
</ttChild>
</ttParent>
</dsMyDataset>


Now when I rewrite this into a dataset where only the temptables are defined and the relations are added later:

// Definition of temp-tables same as above

DEF DATASET dsMyDynamicDataset
FOR ttParent, ttChild.

DATASET dsMyDynamicDataset:ADD-RELATION (
BUFFER ttParent:HANDLE, BUFFER ttChild:HANDLE,
"pKey,iParent",
FALSE, TRUE, FALSE, FALSE, TRUE).

// Filling of temp-tables same as above

DATASET dsMyDynamicDataset:WRITE-XML("FILE", "C:/temp/testDs.xml").


I would expect the same result as above but this is the result I get instead:

<?xml version="1.0"?>
<dsMyDynamicDataset xmlns:xsi="http://www.w3.org/2001/XMLSchema-instance">
<ttParent>
<pKey>1</pKey>
<parentName>Parent</parentName>
</ttParent>
<ttChild>
<childName>Child</childName>
</ttChild>
<ttChild>
<childName>Child2</childName>
</ttChild>
</dsMyDynamicDataset>

Continue reading...