休眠：@ManyToOne(fetch = FetchType.LAZY) 对非主键引用列不起作用

Question

I have 2 tables: Order [OrderId(PK), OrderShipmentCode, ...] and Shipment[ShipmentId(PK), ShipmentCode, ...] .

In Order class, I declared shipment field as follows:

@ManyToOne(fetch = FetchType.LAZY)
@JoinColumn(name = "OrderShipmentCode", referencedColumnName = "ShipmentCode", insertable = false, updatable = false, nullable = false)
private Shipment shipment;

When I get the list of Order , the Shipment is also loaded (I saw many separate SELECT queries). But I want the Shipment to be lazy loaded, not to be fetched together with Order .

For other tables, if the referenced column is primary key then the results are as expected (Lazy-loading is used). In my case, ShipmentCode is not Primary Key of Shipment table, and lazy-loading is not used by Hibernate.

Could you show me how to accomplish that goal?

EDIT: The Query code is as bellow:

Criteria criteria = HibernateUtil.getSessionFactory().getCurrentSession().createCriteria(Order.class);
List result = criteria.list();

SQL queries are: 1 SELECT statement for Order table and a bunch of SELECT statement for Shipment

Answer 1

Thd problem is caused by the HHH-13024 issue .

In the true spirit of OSS, you might want to investigate the problem and send a Pull Request with a fix proposal. That's the fastest way of getting an issue fixed.

Answer 2

Try this:

Criteria criteria = HibernateUtil.getSessionFactory()
                                 .getCurrentSession()
                                 .createCriteria(Order.class)
                                 .setFetchMode("shipment", FetchMode.LAZY);

Answer 3

You can use @JsonIgnore over the shipment field of order. If you are giving using MappedBy over shipment field then removing it might solve your issue.

Answer 4

add to your entity field with shipmentCode and set your code for relation, then it`s fork fine

@Column(name = "shipmentCode")
private Long shipmentCode;

@ManyToOne(fetch = FetchType.LAZY)
@JoinColumn(name = "OrderShipmentCode", referencedColumnName = "shipmentCode", insertable = false, updatable = false, nullable = false)
private Shipment shipment;

If you use Lazy-init you entity extracting without fild with relation value, then when you trying extract lazy entity Hibernate can`t find any values becouse it havent relation value

Answer 5

If you worry about multiple select queries while loading, you can overcome this by using Entity Graphs. please refer to below link for more details https://www.baeldung.com/spring-data-jpa-named-entity-graphs