多对多

[lzf715]

@Table("test_book")
public class PaperGroup extends IdEntity {
    @Name
    private String no;
    private String title;
    private String memo;
    private String creator;
    private String introduction;
    private Date createdTime;
    private String branch;
    private int orderNum;
@ManyMany(target = Paper.class, relation = "test_book_paper", from = "bookNo", to = "paperId", key = "no")
    private List<Paper> papers;

}
public class Paper extends IdEntity {
    @Name
    private String no;
    private String name;
    private String yearly;
    private Date createdTime;
    private Date modifiedTime;
    private int modifiedCount;
    private String status;
    @Many(target = PaperQuestion.class, field = "paperId")
    private List<Question> questions;
}

中间表：id，bookNo，paperid

List<PaperGroup> groupList = this.query(Cnd.where("status", "=",
                Constants.STATUS_VALID));
for (int i = 0; i < groupList.size(); i++) {
            dao().fetchLinks(groupList.get(i), "papers");
        }
}

执行的sql

2013-11-05 10:08:50 DEBUG [http-9191-1] SELECT * FROM test_paper  WHERE id IN (SELECT paperId FROM test_book_paper WHERE bookNo=1)
2013-11-05 10:08:50 DEBUG [http-9191-1] SELECT * FROM test_paper  WHERE id IN (SELECT paperId FROM test_book_paper WHERE bookNo=2)
2013-11-05 10:08:50 DEBUG [http-9191-1] SELECT * FROM test_paper  WHERE id IN (SELECT paperId FROM test_book_paper WHERE bookNo=3)
2013-11-05 10:08:50 DEBUG [http-9191-1] SELECT * FROM test_paper  WHERE id IN (SELECT paperId FROM test_book_paper WHERE bookNo=4)
2013-11-05 10:08:50 DEBUG [http-9191-1] SELECT * FROM test_paper  WHERE id IN (SELECT paperId FROM test_book_paper WHERE bookNo=5)
2013-11-05 10:08:50 DEBUG [http-9191-1] SELECT * FROM test_paper  WHERE id IN (SELECT paperId FROM test_book_paper WHERE bookNo=6)

[zozoh]

你的问题是什么？

[lzf715]

设置的key是no 实际还是通过id对应的

[zozoh]

哦，请参看 @ManyMany 注解的说明

默认的优先会采用 @Id 来对应

但是，我们虽然实现了，但是没有写在文档里，你可以

@ManyMany(target = Paper.class, 
                    relation = "test_book_paper", 
                    from = "bookNo:no", 
                    to = "paperId")
private List<Paper> papers;

来指定 bookNo 的 Java 字段是 'no' 字段。

无论 from 还是 to 都支持这个用法：

   通过冒号分隔，可以指定 Java 字段的名字

你可以看看相关的逻辑 是怎么实现的就明白了

另，你的 "key" 是没必要的，只有当你的 Java 集合是 Map 的时候，才需要你指定一个 key 是从哪个字段提取的

我会补充这部分内容到文档里，这个 Issue 你别关，到时候我来关

[lzf715]

非常感谢。。