I understand the error.Is because you have a pk "party_id" in the table "party" and the same like fk in the table "person" .And I create only the fk with this code .
<service name="createPracticePerson" default-entity-name="Person" engine="entity-auto"
location="component://practice/script/org/practice/practice/PracticeServices.xml" invoke="create" auth="true"> <description>Create a Person</description>