mysql - @OneToOne 映射为 @OneToMany

Question

//@OneToOne 关系通过 Spring data JPA///hibernate in MySQL 映射为 @OneToMany

@Entity
@Table(name = "product")
public class Product extends DataJournal {

    @Id
    @GeneratedValue(strategy = GenerationType.IDENTITY)
    private Long id;
    private String name;
    private Double price;

    private Date dom;
    private Date expiryDate;

    @OneToOne(mappedBy = "product", optional = false)
    private Stock stock;
    //getters and setters
}

@Entity
@Table(name = "stock")
public class Stock extends DataJournal {

    @Id
    @GeneratedValue(strategy = GenerationType.IDENTITY)
    private Long id;
    private Long quantity;
    private Long reOrderLabel;

    @OneToOne
    @JoinColumn(name="product_id")
    private Product product;
    //getters and setters
}

//Product 和 stock 之间的关系是 @OneToOne 但在 Mysql 中被映射为//as @OneToMany，以下是反向的 mysql 数据库和//关系 [1]:https://imgur.com/a/OqC0Ddt [2]:https://imgur.com/a/3fFMuDD

Answer 1

如果您让 Hibernate 为您生成 DDL，请尝试使用 @JoinColumn(unique = true)在您的 Stock 类中:

@Entity
@Table(name = "stock")
public class Stock extends DataJournal {

    @Id
    @GeneratedValue(strategy = GenerationType.IDENTITY)
    private Long id;
    private Long quantity;
    private Long reOrderLabel;

    @OneToOne
    @JoinColumn(name="product_id", unique = true)
    private Product product;
    //getters and setters
}