间接关联

模型

@EqualsAndHashCode(callSuper = true)
@Data
@Model(title = "用户")
public class User extends BaseModel {

    @Column(title = "ID")
    @Primary
    @DefaultOrder
    private String id;

    @Column(title = "名字")
    private String name;

}

@EqualsAndHashCode(callSuper = true)
@Data
@Model(title = "文章")
public class Article extends BaseModel {

    @Column(title = "ID")
    @Primary
    @DefaultOrder
    private String id;

    @Column(title = "标题")
    private String title;

    @Column(title = "作者ID")
    private String uid;

    @Column(title = "所属分组ID")
    private String groupId;

}

@EqualsAndHashCode(callSuper = true)
@Data
@Model(title = "分组")
public class Group extends BaseModel {

    @Column(title = "ID")
    @Primary
    @DefaultOrder
    private String id;

    @Column(title = "分组名称")
    private String name;

}

@EqualsAndHashCode(callSuper = true)
@Data
@Model(title = "标签")
public class Tag extends BaseModel {

    @Column(title = "ID")
    @Primary
    @DefaultOrder
    private String id;

    @Column(title = "标签名称")
    private String name;

}

@EqualsAndHashCode(callSuper = true)
@Data
@Model(title = "文章标签中间表")
public class ArticleTag extends BaseModel {

    @Column(title = "ID")
    @Primary
    @DefaultOrder
    private String id;

    @Column(title = "文章ID")
    private String articleId;

    @Column(title = "文章ID")
    private String tagId;

}

@EqualsAndHashCode(callSuper = true)
@Data
@Model(title = "评论")
public class Comment extends BaseModel {

    @Column(title = "ID")
    @Primary
    @DefaultOrder
    private String id;

    @Column(title = "父级ID")
    private String parentId;

    @Column(title = "发送者")
    private String uid;

    @Column(title = "回复评论ID")
    private String replyCommentId;
    
//    一般可以设计一些冗余字段，优化这种间接关联，此处注释方便示例
//    @Column(title = "回复评论用户ID")
//    private String replyCommentUid;

}

一对一

@EqualsAndHashCode(callSuper = true)
@Data
@Model(table = false)
public class CommentModel extends Comment {

    //    left join user on user.id[主键] = comment.uid[关联键]
    @Join(rightJoinField = "uid")
    private User sender;

    //    自关联，不常用
    //    left join comment as replyComment on replyComment.id[主键] = comment.replyCommentId[关联键]
    @Join(rightJoinField = "replyCommentId")
    private Comment replyComment;
        
    //    left join user as replyCommentSender on replyCommentSender.id[主键] = replyComment.uid[关联键]
    @Join(rightJoinField = "uid", indirectJoinField = "replyComment")
    private User replyCommentSender;

}

一对多

此类间接关联是完全禁用的，一是设计基于当前模型避免间接查询扩散，因此完全不可用，二是仍会导致 _getList 返回扁平化数据的分页异常

使用以下写法避免，需要的时候传入 articleId 做一次查询即可，同时可以在 Article 中做 tagList 的冗余 json 字段，方便实际使用

@EqualsAndHashCode(callSuper = true)
@Data
@Model(table = false)
public class ArticleTagModel extends ArticleTag {
    
    //    left join tag on tag.id[主键] = articleTag.tagId[关联键]
    @Join(rightJoinField = "tagId")
    private Tag tag; 

}