Question

我有两个与多对多关系相关的类：

Book.java

@Entity
@Table(name = "book")
public class Book {
    @Id
    @GeneratedValue(strategy = GenerationType.IDENTITY)
    @Column(name = "book_id")
    private Long id;
    @Column(nullable = false)
    private String title;
    private String description;
    @Column(name = "release_date")
    @Temporal(TemporalType.TIMESTAMP)
    private Date releaseDate;
    @JoinColumn(name = "cover_image")
    @OneToOne(cascade = CascadeType.MERGE)
    private UploadFile coverImage;
    @OneToOne(cascade = CascadeType.MERGE)
    private UploadFile content;
    @ManyToMany(cascade = CascadeType.ALL)
    @JoinTable(name = "book_category", joinColumns = {@JoinColumn(name = "book_id", referencedColumnName = "id")},
        inverseJoinColumns = {@JoinColumn(name = "category_id", referencedColumnName = "id")})
    private Set<Category> categories;
}

Category.java

@Entity
@Table(name = "category")
public class Category {
    @Id
    @GeneratedValue(strategy = GenerationType.IDENTITY)
    @Column(name = "category_id")
    private Long id;
    @Column(name = "category_name")
    private String name;
    @ManyToMany(mappedBy = "categories", fetch = FetchType.LAZY) // I also tried an option with adding cascade = CascadeType.ALL
    private List<Book> books;
}

当我想将书添加到数据库时，出现以下异常：

org.springframework.dao.InvalidDataAccessApiUsageException: detached entity passed to persist: com.github.model.Category; nested exception is org.hibernate.PersistentObjectException: detached entity passed to persist: com.github.model.Category

有趣的是，从Category类中删除@GeneratedValue批注会使所有事情都尽可能正常地工作。要添加书，我扩展了JpaRepository：

public interface Repository extends JpaRepository<Book, Long>{
}

然后

Repository repository;
repository.save(book);

我正在使用 h2 数据库也应注意的重要事项。要查看所有代码，您可以访问我的github：Why does pip freeze list "pkg-resources==0.0.0"?

编辑

添加@Column批注后，InvalidDataAccessApiUsageException的问题已解决。但是，出现映射收集问题。这是我收到的堆栈跟踪：

java.lang.IllegalStateException: Failed to load ApplicationContext
Caused by: org.springframework.beans.factory.BeanCreationException: Error creating bean with name 'entityManagerFactory' defined in class path resource [org/springframework/boot/autoconfigure/orm/jpa/HibernateJpaConfiguration.class]: Invocation of init method failed; nested exception is org.hibernate.AnnotationException: Unable to map collection com.github.model.Book.categories
Caused by: org.hibernate.AnnotationException: Unable to map collection com.github.model.Book.categories
Caused by: org.hibernate.cfg.RecoverableException: Unable to find column with logical name: id in org.hibernate.mapping.Table(book) and its related supertables and secondary tables
Caused by: org.hibernate.MappingException: Unable to find column with logical name: id in org.hibernate.mapping.Table(book) and its related supertables and secondary tables

编辑2

当我在@JoinTable中将referencedColumnName从id更改为book_id时，我收到了如下所示的DataIntegrityViolationException：

org.springframework.dao.DataIntegrityViolationException: could not execute statement; SQL [n/a]; constraint ["FKAM8LLDERP40MVBBWCEQPU6L2S: PUBLIC.BOOK_CATEGORY FOREIGN KEY(CATEGORY_ID) REFERENCES PUBLIC.CATEGORY(CATEGORY_ID) (1)"; SQL statement:
insert into book_category (book_id, category_id) values (?, ?) [23506-196]]; nested exception is org.hibernate.exception.ConstraintViolationException: could not execute statement

Answer 1

可能的解决方案1：删除(cascade = CascadeType.ALL)

可能的解决方案2：在(cascade = CascadeType.ALL)中添加@ManyToMany(mappedBy = "categories", fetch = FetchType.LAZY,cascade = CascadeType.ALL)

请参阅：https://stackoverflow.com/a/45781533/6572971

注释@GeneratedValue导致InvalidDataAccessApiUsageException

1 个答案: