Rewriting Derby DB tables (with FK) via JPA - jpa

Question

I can fill 2 tables in a DB where the tables have mappings(one table has a FK from he other). The
EclipseLink DataSource show the flush to the DB has been done ok.
I am trying to rewrite the tables (with same data a second time ) while the persistence.xml has
the properties clause as follows :
<property name="eclipselink.ddl-generation" value="drop-create-tables" />
yet I see no dropping (erase) of the previous tables before the rewriting and therefore get rejected with the following exception message about a duplicate key :
"Internal Exception:
java.sql.SQLIntegrityConstraintViolationException: The statement was
aborted because it would have caused a duplicate key value in a unique
or primary key constraint or unique index identified by
'SQL120206135740510' defined on 'HOST'. " ( HOST is the table pointed
to by the FK).
What am I missing in the persistence.xml or else that should make the table drop before the rewrite ?
Below see the persistence.xml file ( the DB file is called 'test' . The schema is name after the user name (APP in my case) ):
<?xml version="1.0" encoding="UTF-8"?>
<persistence version="2.0" xmlns="http://java.sun.com/xml/ns/persistence" xmlns:xsi="http://www.w3.org/2001/XMLSchema-instance" xsi:schemaLocation="http://java.sun.com/xml/ns/persistence http://java.sun.com/xml/ns/persistence/persistence_2_0.xsd">
<persistence-unit name="jpa_test">
<class>Host</class>
<class>Vm</class>
<properties>
<property name="javax.persistence.jdbc.url" value="jdbc:derby://im6-64s:1527/test;create=true" />
<property name="javax.persistence.jdbc.user" value="APP" />
<property name="javax.persistence.jdbc.password" value="passw0rd" />
<!-- EclipseLink should create the database schema automatically -->
<property name="eclipselink.ddl-generation" value="drop-create-tables" />
<property name="eclipselink.ddl-generation.output-mode" value="database" />
</properties>
</persistence-unit>
</persistence>

Answer 1

"drop-create-tables" should be "drop-and-create-tables"

Answer 2

Try adding the "eclipselink.logging.level" property with a value of Finest or ALL to see why the drop might not be being executed.