Question

我对Web编程和hibernate / jpa等还有些陌生。我正在使用maven / jpa / hibernate进行动态Web项目。

我已经成功创建了用户页面和系列页面，但是当我尝试添加评论时出现错误：

ERROR: Table 'webproject.user_series_review' doesn't exist
org.hibernate.exception.SQLGrammarException: could not extract ResultSet

但是我检查了几次，但是我没有这样的表或fk，所以我也不从任何地方调用此表。

休眠地图：

评论：

@Entity(name="series_review")
    @Table(name="series_review")
    public class SeriesReview {

        @Id
        @Column(name="id", updatable = false, nullable = false)
        private int id;

        @Column(nullable=false)
        private String review;
        @Column(nullable=false)
        private Date date;

        @ManyToOne
        @JoinColumn(name = "fk_user", insertable = false, updatable = false)
        private User user;

        @ManyToOne
        @JoinColumn(name = "fk_series", insertable = false, updatable = false)
        private Series series;

        @OneToMany(cascade = CascadeType.ALL, orphanRemoval = true)
        private List<Comment> comments = new ArrayList<Comment>();

用户：

@Entity(name="user")
    @Table(name="user")
    @NamedQueries({..})
    public class User implements Serializable {

        @Id
        @Column(name="id", updatable = false, nullable = false)
        private int id;

        private String name;

        ....

        @ManyToMany
        @JoinTable(name = "fav_series",
                    joinColumns = { @JoinColumn(name="fk_user") },
                    inverseJoinColumns = { @JoinColumn(name="fk_series") })
        private List<Series> favoriteSeries = new ArrayList<Series>();

        @OneToMany(cascade = CascadeType.ALL, orphanRemoval = true)
        private List<SeriesReview> reviews = new ArrayList<SeriesReview>();

        @OneToMany(cascade = CascadeType.ALL, orphanRemoval = true)
        private List<Comment> comments = new ArrayList<Comment>();

系列：

@Entity
    @Table(name = "series")
    @NamedQueries({ @NamedQuery(name = "allSeries", query = "SELECT s FROM Series s"),
            @NamedQuery(name = "findSeriesByName", query = "SELECT s FROM Series AS s WHERE s.name = :name"),
            @NamedQuery(name = "topRatedSeries", query = "SELECT DISTINCT s FROM Series AS s ORDER BY s.imdb_rating DESC"),
            @NamedQuery(name = "seriesType", query = "SELECT s FROM Series AS s WHERE s.genre = :type"),
            @NamedQuery(name = "findByID", query = "SELECT s FROM Series AS s WHERE s.id = :id")
    })
    public class Series {

        @Id
        @Column(name = "id", updatable = false, nullable = false)
        private int id;

        @Column(nullable = false, unique = true)
        private String name;

        private String info;
        private String start_year;
        private String end_year;
        private Double imdb_rating;
        private int site_rating;
        private String video;
        private String image;
        private String genre;
        private String director;
        private String cast;
        private String creator;

        @ManyToMany
        @JoinTable(name = "fav_series", joinColumns = { @JoinColumn(name = "fk_series") }, inverseJoinColumns = {
                @JoinColumn(name = "fk_user") })
        private List<User> fans = new ArrayList<User>();

        @OneToMany(cascade = CascadeType.ALL, orphanRemoval = true)
        private List<SeriesReview> reviews = new ArrayList<SeriesReview>();

我添加评论代码：

public class ReviewService {

        private EntityManagerFactory emf;
        private EntityManager em;
        private EntityTransaction tx;

        public ReviewService() {
            emf = Persistence.createEntityManagerFactory("WebProject");
            em = emf.createEntityManager();
            tx = em.getTransaction();
            em.getTransaction().begin();
        }

        public Boolean insert(SeriesReview review, int userID, int seriesID) {
            try {
                User user = em.find(User.class, userID);
                review.setUser(user);
                user.getReviews().add(review);
                Series series = em.find(Series.class, seriesID);
                review.setSeries(series);
                series.getReviews().add(review);
                em.persist(review);
                tx.commit();

                return true;
                }
                catch(Exception e){
                    System.out.println(e);
                    return false;
                }
        }

    }

我的数据库的一部分：

DROP TABLE IF EXISTS `user`;
SET character_set_client = utf8mb4 ;
CREATE TABLE `user` (
  `id` int(11) NOT NULL AUTO_INCREMENT,
  `name` varchar(255) DEFAULT NULL,
  `email` varchar(255) NOT NULL,
  `username` varchar(255) NOT NULL,
  `password` varchar(255) DEFAULT NULL,
  `photo` varchar(255) DEFAULT NULL,
  `role_type` int(11) NOT NULL DEFAULT '0',
  `created_at` date NOT NULL,
  PRIMARY KEY (`id`),
  UNIQUE KEY `email_UNIQUE` (`email`),
  UNIQUE KEY `username_UNIQUE` (`username`)
) ENGINE=InnoDB DEFAULT CHARSET=utf8;

DROP TABLE IF EXISTS `series`;
 SET character_set_client = utf8mb4 ;
CREATE TABLE `series` (
  `id` int(11) NOT NULL AUTO_INCREMENT,
  `name` varchar(100) NOT NULL,
  `info` mediumtext,
  `start_year` varchar(70) DEFAULT NULL,
  `end_year` varchar(70) DEFAULT NULL,
  `imdb_rating` decimal(10,0) DEFAULT NULL,
  `site_rating` decimal(10,0) DEFAULT NULL,
  `video` varchar(255) DEFAULT NULL,
  `image` varchar(255) DEFAULT NULL,
  `genre` varchar(255) NOT NULL,
  `cast`  varchar(255) DEFAULT NULL,
  `director` varchar(255) DEFAULT NULL,
  `creator` varchar(255) DEFAULT NULL,
  PRIMARY KEY (`id`),
  UNIQUE KEY `id_UNIQUE` (`id`),
  UNIQUE KEY `name_UNIQUE` (`name`)
) ENGINE=InnoDB DEFAULT CHARSET=utf8;

DROP TABLE IF EXISTS `series_review`;
 SET character_set_client = utf8mb4 ;
CREATE TABLE `series_review` (
  `id` int(11) NOT NULL AUTO_INCREMENT,
  `user_id` int(11) NOT NULL,
  `series_id` int(11) NOT NULL,
  `review` longtext NOT NULL,
  `date` DATETIME DEFAULT NOW(),
  PRIMARY KEY (`id`,`user_id`,`series_id`),
  KEY `user_id_INDEX` (`user_id`),
  KEY `series_id_INDEX` (`series_id`),
  CONSTRAINT `fk_series_review_series1` FOREIGN KEY (`series_id`) REFERENCES `series` (`id`),
  CONSTRAINT `fk_series_review_user1` FOREIGN KEY (`user_id`) REFERENCES `user` (`id`)
) ENGINE=InnoDB DEFAULT CHARSET=utf8;

Answer 1

由于您没有为此映射定义mapply(rnorm, n = 3, mean = V, sd = VU)属性

mappedBy

Hibernate正在寻找您没有的联接表

将其更改为

@OneToMany(cascade = CascadeType.ALL, orphanRemoval = true)
private List<SeriesReview> reviews = new ArrayList<SeriesReview>();

错误：表'webproject.user_series_review'不存在org.hibernate.exception.SQLGrammarException：无法提取ResultSet

1 个答案: