Question

I am creating an application with eclipselink JPA, I am using HistoryPlicy to create historical data. Every thing is working fine, but I am facing a problem with copying blob data to history table.

@Entity
@Customizer(AttachmentHistoryPolicy.class)
@Table(name = "STAFF_ATTACHMENT", catalog = "", schema = "OIA")
public class Attachment implements Serializable {
    @Id
    private Long id;
    @Basic(optional = false)
    @NotNull
    @Lob
    @Column(name = "CONTENTS")
    private byte[] contents;

    // getters and setters
}


public class AttachmentHistoryPolicy implements DescriptorCustomizer {

    @Override
    public void customize(ClassDescriptor cd) throws Exception {
        HistoryPolicy policy = new HistoryPolicy();
        policy.addHistoryTableName("HIST_STAFF_ATTACHMENT");
        policy.addStartFieldName("HIST_START_DATE");
        policy.addEndFieldName("HIST_END_DATE");
        policy.setShouldHandleWrites(true);
        //policy.useDatabaseTime();
        cd.setHistoryPolicy(policy);
    }

}

the row is inserted in the history table, but with empty blob!!!

is there a way to handle this using eclipselink HistoryPolicy ?

EDIT:

following are the sql statements generated by eclipselink

BEGIN INSERT INTO OIA.STAFF_ATTACHMENT (ID, CONTENT_TYPE, CONTENTS, FILE_NAME, FILE_SIZE, OWNER, STAFF_MEMBER) VALUES (?, ?, ?, ?, ?, ?, ?) RETURNING CONTENTS INTO ?; END;

SELECT CONTENTS FROM OIA.STAFF_ATTACHMENT WHERE (ID = ?) FOR UPDATE

INSERT INTO HIST_STAFF_ATTACHMENT (ID, CONTENT_TYPE, CONTENTS, FILE_NAME, FILE_SIZE, OWNER, STAFF_MEMBER, HIST_START_DATE) VALUES (?, ?, ?, ?, ?, ?, ?, ?)

SELECT CONTENTS FROM OIA.STAFF_ATTACHMENT WHERE (ID = ?) FOR UPDATE
bind => [1 parameter bound]

note the tow identical statements for select contents for update (the two statements are for STAFF_ATTACHMENT table)

Answer 1

Seems to be an issue with EclipseLink’s support for history in combination of LOB locator support for Oracle platforms.

Please log a bug, but if you are using Oracle 11, then I think LOB now work without a locator, so the workaround is no longer required. Try setting the platform to Oracle11, or just use OraclePlatform which does not use the locator.