Hello everyone,
I have detected that toplink sends strange queries to the database. For
example, one of JPA queries I do
is
SELECT DISTINCT booking FROM BookingEntity booking WHERE
booking.passengerSegments.openSegmentReservationDeadline IS NOT NULL AND
booking.passengerSegments.openSegmentReservationDeadline < "2008-11-19
17:05:12" AND booking.passengerSegments.objectStatus = "ACT" AND
booking.passengerSegments.reservationStatus = "OP"
Toplink translates this query into the following SQL statement:
ELECT DISTINCT t0.res_booking_id, t0.is_pnr_compatible, t0.is_group_booking,
t0.creation_datetime, t0.currency_code, t0.record_locator, t0.comments,
t0.requested_ticketing_time, t0.object_status_code, t0.is_pending,
t0.emergency_locked, t0.reservation_datetime, t0.handling_fee,
t0.ticketing_time_limit, t0.external_record_locator,
t0.res_contact_person_id, t0.sec_user_id FROM res_passenger_segment t4,
res_passenger_segment t3, res_passenger_segment t2, res_passenger_segment
t1, res_booking t0 WHERE ((((NOT ((t1.open_segment_reservation_deadline IS
NULL)) AND (t2.open_segment_reservation_deadline < ?)) AND
(t3.object_status_code = ?)) AND (t4.reservation_status_code = ?)) AND
((((t1.res_booking_id = t0.res_booking_id) AND (t2.res_booking_id =
t0.res_booking_id)) AND (t3.res_booking_id = t0.res_booking_id)) AND
(t4.res_booking_id = t0.res_booking_id)))
bind => [2008-11-19 17:05:12.0, ACT, OP]
As you can see, the query has redundant joins on res_passenger_segment
My mappped classes are
@Entity
@EntityListeners(GuardedObjectListener.class)
@Table(name = BookingEntity.TABLENAME)
public class BookingEntity implements Booking {
...........
@OneToMany(targetEntity = PassengerSegmentEntity.class, mappedBy =
PassengerSegment.FIELD_BOOKING,
fetch = FetchType.LAZY, cascade = {CascadeType.PERSIST,
CascadeType.MERGE, CascadeType.REFRESH })
private List<PassengerSegment> passengerSegments = new
ArrayList<PassengerSegment>();
}
@Entity
@Table(name = PassengerSegmentEntity.TABLENAME)
public class PassengerSegmentEntity implements PassengerSegment {
.............
@ManyToOne(targetEntity = BookingEntity.class, fetch = FetchType.LAZY)
@JoinColumn(name = COLUMN_RES_BOOKING_ID, nullable = false)
private Booking booking;
public static final String COLUMN_RES_BOOKING_ID = "res_booking_id";
}
I use ToplinkEssentials 10.1.3 and MySQL 5.0, jdk 1.5.0_16
Does anybody know why I have redundant joins ?
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