JPA更新在多对多关系中不起作用 [英] JPA update doesn't work in a many-to-many relationship

问题描述

我有3张桌子:

• customer(idCustomer,...)
• is_managed(idCustomer,idPerson)
• sales_person(idPerson,...)

• customer(idCustomer,...)
• is_managed(idCustomer,idPerson)
• sales_person(idPerson,...)

customer和sales_person之间存在@ManyToMany关系.

当我执行删除操作时，它可以正常工作:删除customer，is_managed和sales_person.

When I perform a delete, then it works fine: the customer, is_managed and sales_person are deleted.

但是，当我执行更新时，会更新customer和is_managed，但不会更新sales_person.

But when I perform an update, then the customer and is_managed are updated, but the sales_person not.

例如，如果我通过删除sales_person来更新customer，则会在is_managed表中将其删除，但不会在sales_person表中将其删除.

For example, if I update a customer by deleting the sales_person, it's deleted in is_managed table, but not in sales_person table.

这是怎么引起的，我该如何解决?

How is this caused and how can I solve it?

以下是相关代码:

// update customer
public String updateCustomer(Customer customer,ArrayList<Sales_person> sales_persons,ArrayList<Involved_group_relation> involved_groups, Macro_market macro_market)throws IOException {

   // insert the sales_person attached to the customer
   ArrayList<Sales_person> sales_personC = new ArrayList<Sales_person>();
   sales_personC.addAll(sales_persons);

    customer.setSalesPersons_BelongTo(sales_personC); // insert in customer the sales_persons

    em.merge(customer);
    return customer.getNameCustomer();
}

// entity customer
@Entity
@Table(name="customer")
public class Customer implements Serializable {

    private static final long serialVersionUID = 1L;

    @Id
    @GeneratedValue( strategy = GenerationType.IDENTITY)
    private Long idCustomer;

    private String titleTypeAccount;
    private String nameCustomer;

    /** RELATIONS **/
    // CUSTOMER - SALES_PERSON
    @ManyToMany(
            cascade={CascadeType.ALL}
    )
    @JoinTable(
        name="is_managed",
        joinColumns=@JoinColumn(name="idCustomer"),
        inverseJoinColumns=@JoinColumn(name="idPerson")
    )
    private Collection<Sales_person> salesPersons_BelongTo;
        ...
        ...

// entity sales_person
@Entity
@Table(name="sales_person")
public class Sales_person implements Serializable {

    private static final long serialVersionUID = 1L;

    @Id
    private Long idPerson;

    private String nameSalesPerson;
    private String jobFunction;
    private String titleOrganization;

    @ManyToMany(
        mappedBy="salesPersons_BelongTo"
    )
    private Collection<Customer> customers;
    ...
    ...

推荐答案

如果要从数据库中删除SalesPerson，则必须在SalesPerson上调用em.remove().仅仅调用merge()还不够.

If you want the SalesPerson to be deleted from the database, then you must call em.remove() on the SalesPerson. Calling merge() is not enough.

此外，如果您希望合并SalesPerson的更改，则还必须在SalesPerson上调用merge()，或在salesPersons_BelongTo关系上设置级联合并.

Also, if you want the SalesPerson's changes to be merged, you must call merge() on the SalesPerson as well, or set cascade merge on the salesPersons_BelongTo relationship.

还要确保您保持双向关系的双方，而不仅仅是一侧.

Also ensure you are maintaining both sides of the bi-directional relationship, not just one side.

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