Error "Each row in the Query Result Columns must be mapped to a unique Query Attribute in Mapped Entity columns" while extending a VO

I was trying to extend the seeded iProcurement VO “ReqsApprovalsVO” with out adding any custom attributes.

When I clicked “Next” button on the Step 4/7 (Attribute Mappings), I hit this roadblock which keeps saying “Each row in the Query Result Columns must be mapped to a unique Query Attribute in Mapped Entity columns” and does not let me extend the VO after this.

I thought of several reasons which could be causing this error. I thought it had something do with the file version of the seeded VO I am trying to extend or it could be due to the jDeveloper version I am using.

I ruled out all the possibilities one by one including the jDeveloper issues. Then I looked in metalink and one of the notes gave me a little clue which would solve my issue.

Source: Metalink Note: 1524622.1

I went back to the seeded VO to see if any of the attributes are having this issue. Right Click on “ReqsApprovalsVO” à Edit ReqsApprovalsVO

I found this attribute OrgId which is “Mapped to Column or SQL” and has the Query column as “OrgId”

When I verified the SQL Statement for this VO, OrgId attribute has been pulled as “Org_Id” in the query which is not same as “OrgId” and this explains me why the error has been occurring when I am trying to extend the VO.

To resolve the issue, I changed the OrgId to ORG_ID in the seeded VO and was able to extend the VO there after.