@Entity
@Inheritance(strategy=InheritanceType.JOINED)
@Table(name="PAE")
@DiscriminatorColumn(name="DTYPE", discriminatorType=DiscriminatorType.STRING,length=20)
@DiscriminatorValue("R")
public class PersistentAccountancyEntry implements AccountancyEntry {
	@EmbeddedId
	@AttributeOverride(name="id", column=@Column(name="ENTRY_ID"))
	private AccountancyEntryIdentifier accountancyEntryIdentifier;

@Entity
@Table(name="PPE")
@DiscriminatorValue("P")
public class ProductPaymentEntry extends PersistentAccountancyEntry
{
	@Embedded
	@AttributeOverride(name = "id", column = @Column(name = "ORDER_ID"))
	private OrderIdentifier orderIdentifier;

	@Embedded
	@AttributeOverride(name = "id", column = @Column(name = "UID"))
	private UserIdentifier userIdentifier;

[EL Fine]: Connection(941535430)--DROP TABLE PAE
[EL Fine]: Connection(941535430)--CREATE TABLE PAE (DTYPE VARCHAR(20), DATE TIMESTAMP, DESCRIPTION VARCHAR(255), VALUE BLOB(2147483647), ENTRY_ID VARCHAR(255))
[EL Fine]: Connection(941535430)--DROP TABLE PPE
[EL Fine]: Connection(941535430)--CREATE TABLE PPE (ENTRY_ID VARCHAR(255) NOT NULL, ORDER_ID VARCHAR(255), UID VARCHAR(255) NOT NULL, PRIMARY KEY (ENTRY_ID, UID))

	EntityManager em = emf.createEntityManager();
		CriteriaBuilder cb = em.getCriteriaBuilder();
		CriteriaQuery<PersistentAccountancyEntry> q = cb
				.createQuery(PersistentAccountancyEntry.class);
		Root<PersistentAccountancyEntry> r = q
				.from(PersistentAccountancyEntry.class);
		Predicate p = cb.between(r.get(PersistentAccountancyEntry_.date),
				from.toDate(), to.toDate());
		q.where(p);
		TypedQuery<PersistentAccountancyEntry> tq = em.createQuery(q);

[EL Warning]: 2011-09-23 18:38:44.388--UnitOfWork(1237880619)--Exception [EclipseLink-6044] (Eclipse Persistence Services - 2.3.0.v20110604-r9504): org.eclipse.persistence.exceptions.QueryException
Exception Description: The primary key read from the row [ArrayRecord(
	PAE.DTYPE => R
	PAE.DATE => 2011-09-23 18:38:37.219
	PAE.DESCRIPTION => null
	PAE.VALUE => [B@6153e0c0
	PAE.ENTRY_ID => 45aabaaf-cf87-4261-b0b0-f13a8b5e5ead)] during the execution of the query was detected to be null.  Primary keys must not contain null.
Query: ReadAllQuery(referenceClass=PersistentAccountancyEntry sql="SELECT DISTINCT DTYPE FROM PAE WHERE (DATE BETWEEN ? AND ?)")

@SuppressWarnings("serial")
@Embeddable
@MappedSuperclass
public class SalespointIdentifier implements Serializable, Comparable<SalespointIdentifier>
{
	private String id;

	public SalespointIdentifier()
	{
		id = UUID.randomUUID().toString();
	}
...
}

@SuppressWarnings("serial")
@Embeddable
public final class AccountancyEntryIdentifier extends SalespointIdentifier {
	public AccountancyEntryIdentifier() {
		super();
	}

	@Deprecated
	public AccountancyEntryIdentifier(String identifier) {
		super(identifier);
	}
}

@Entity
public class PersistentAccountancyEntry implements AccountancyEntry {
	@EmbeddedId
	@AttributeOverride(name = "id", column = @Column(name = "ENTRY_ID", nullable = false))
	private AccountancyEntryIdentifier accountancyEntryIdentifier = new AccountancyEntryIdentifier();
...

@Entity
public class ProductPaymentEntry extends PersistentAccountancyEntry {
	/**
	 * The <code>OrderIdentifier</code> to which this
	 * <code>ProductPaymentEntry</code> refers to.
	 */
	@Embedded
	@AttributeOverride(name = "id", column = @Column(name = "ORDER_ID", nullable = true))
	private OrderIdentifier orderIdentifier;

	/**
	 * The <code>UserIdentifier</code> to which this
	 * <code>ProductPaymentEntry</code> refers to.
	 */
	@Embedded
	@AttributeOverride(name = "id", column = @Column(name = "USER_ID", nullable = true))
	private UserIdentifier userIdentifier;
...

[EL Fine]: Connection(1085171660)--CREATE TABLE PERSISTENTACCOUNTANCYENTRY (DTYPE VARCHAR(31), DATE TIMESTAMP, DESCRIPTION VARCHAR(255), VALUE BLOB(2147483647), ENTRY_ID VARCHAR(255) NOT NULL, PAYMENTMETHOD BLOB(2147483647), ORDER_ID VARCHAR(255), USER_ID VARCHAR(255), PRIMARY KEY (ENTRY_ID))