Question

我在hibernate中遇到过一个场景，我试图寻找这样的场景讨论，但我无法在这里争取任何建议或帮助，

我有三个表类别，category_artical，artical。

CREATE TABLE `category` (
  `category_id` int(11) NOT NULL AUTO_INCREMENT,
  `category_name` varchar(45) NOT NULL,
  `category_description` varchar(45) NOT NULL,
  PRIMARY KEY (`category_id`)
);


CREATE TABLE `article` (
  `article_id` int(11) NOT NULL AUTO_INCREMENT,
  `title` varchar(70) NOT NULL,
  `description` varchar(250) NOT NULL,
  `keywords` varchar(150) NOT NULL,
  `content` text NOT NULL,
  PRIMARY KEY (`article_id`)
);

CREATE TABLE `category_article` (
  `category_id` int(11) NOT NULL,
  `article_id` int(11) NOT NULL,
  'category_article_status' varchar(1) NOT NULL.
  'category_article_type' varchar(2) NOT NULL,
  PRIMARY KEY (`category_id`,`article_id`),
  UNIQUE KEY `article_id_UNIQUE` (`article_id`),
  KEY `fk_category` (`category_id`),
  KEY `fk_article` (`article_id`),
  CONSTRAINT `fk_article` FOREIGN KEY (`article_id`) REFERENCES `article` (`article_id`),
  CONSTRAINT `fk_category` FOREIGN KEY (`category_id`) REFERENCES `category` (`category_id`)
);

我有类别的实体，

    @Entity
    @Table(name = "CATEGORY")
    public class Category {

        private long id;
        private String name;

    @Id
    @GeneratedValue
    @Column(name = "CATEGORY_ID")
    public long getId() {
        return id;
    }

    @OneToMany(cascade = CascadeType.ALL)
    @JoinTable(
            name = "CATEGORY_ARTICLE",`enter code here`
            joinColumns = @JoinColumn(name = "CATEGORY_ID"),
            inverseJoinColumns = @JoinColumn(name = "ARTICLE_ID")
    )
    private Set<Article> articles; 
    // other getters and setters...

/*For Article entity is */
    @Entity
    @Table(name = "ARTICLE")
    public class Article {
        private long id;
        private String title;
        private String description;
        private String keywords;
        private String content;

    @Id
    @GeneratedValue
    @Column(name = "ARTICLE_ID")
    public long getId() {
        return id;
    }

    // other getters and setters...

对于category_article，我没有实体，因为我在类别中使用@jointable 所以一切正常，直到我在category_article中只有两列是category_id和article_id。但是，一旦我添加了两个列，我就会混淆如何在那些非空的数据库（category_article_status和category_article_type）中输入数据。

对此有任何建议。

Answer 1

您应该像这样为CATEGORY_ARTICLE创建另一个实体。

@Entity
@Table(name = "CATEGORY_ARTICLE")
public class CategoryArticle{

   @Id
   private Long id;

   @ManyToOne(cascade = CascadeType.ALL)
   @JoinColumn(name = "category_id")  
   private Category category;

   @ManyToOne(cascade = CascadeType.ALL)
   @JoinColumn(name = "article_id")  
   private Article article; 


   // other columns 
   private Boolean categoryArticleStatus;

   private Long categoryArticleType;

}

也应该更改Category和Article。从类别实体中删除JoinTable并将其更改为以下。

<强>分类

@Entity
@Table(name = "CATEGORY")
public class Category {

  //.....

  @OneToMany(mappedBy = "category")
  private Set<CategoryArticle> categoryArticleSet;
}

文章

@Entity
@Table(name = "ARTICLE")
public class Article {

  //.....

  @OneToMany(mappedBy = "article")
  private Set<CategoryArticle> categoryArticleSet;

 }

@OneToMany @JoinTable使用三个表

1 个答案: