java - 使用表键映射一对多

Question

我有主桌商户和副桌交易：

商户：

@Entity
@Table
public class Merchants {

    @Id
    @GeneratedValue(strategy = GenerationType.AUTO)
    @Column(name = "id")
    private int id;

    @Column(length = 255)
    private String name;

交易：

@Entity
@Table
public class PaymentTransactions {

    @Id
    @GeneratedValue(strategy = GenerationType.AUTO)
    @Column(name = "id", updatable = false, nullable = false)
    private int id;

    @Column(length = 4)
    private int reference_transaction_id;

    @ManyToOne(fetch = FetchType.LAZY)
    @JoinColumn(name = "merchant_id")
    private Merchants merchants;

如何将商家 ID（表键）配置为表交易的参考键作为表列merchant_id？

标签： javahibernatejpaspring-data-jpa

Answer 1

我怀疑您是否应该在 @JoinColumn 注释中使用 referencedColumnName 属性，并将 PaymentTransactions 更改为 List：

@Entity
@Table
public class Merchants {

    @Id
    @GeneratedValue(strategy = GenerationType.IDENTITY)
    @Column(name = "id")
    private int id;

    @Column(length = 255)
    private String name;

    @OneToMany(fetch = FetchType.LAZY, cascade = CascadeType.ALL, orphanRemoval = true, mappedBy = "merchant")
    List<PaymentTransactions> transactions;
}

@Entity
@Table
public class PaymentTransactions {

    @Id
    @GeneratedValue(strategy = GenerationType.IDENTITY)
    @Column(name = "id", updatable = false, nullable = false)
    private int id;

    @Column(length = 4)
    private int reference_transaction_id;

    @ManyToOne
    // here referencedColumnName is id column of merchant entity
    @JoinColumn(name = "merchant_id", referencedColumnName = "id", insertable = false, updatable = false) 
    private Merchants merchant;
}