休眠连接表mysql

Question

我有两个简单的表格。

    mysql> select * from filesshare;
+----+--------+--------+-------+
| id | userId | fileId | owner |
+----+--------+--------+-------+
|  1 |      2 |      1 |     1 |
|  2 |      3 |      1 |     1 |
|  3 |      4 |      2 |     1 |
|  4 |      5 |      2 |     1 |
+----+--------+--------+-------+
4 rows in set (0.00 sec)

mysql> select * from filesinfo;
+----+-----------------+-----------------------------------+
| id | name            | url                               |
+----+-----------------+-----------------------------------+
|  1 | dwnld_btn.png   | C:\shareapp\admin\dwnld_btn.png   |
|  2 | dwnld_btn_1.png | C:\shareapp\admin\dwnld_btn_1.png |
+----+-----------------+-----------------------------------+
2 rows in set (0.01 sec)

我现在将有两个值作为输入。 1) 用户 ID 2) 所有者

现在假设 userId=3 和 owner=1。现在我想输出匹配文件共享表中给定值的所有行，在这种情况下，它的第二行是“2 | 3 | 1 | 1”现在我想要第三列的值现在是 1。然后使用该值，我想从 filesinfo 表中检索数据。在这种情况下，filesinfo 表的第一行将输出。像这样：

+----+-----------------+-----------------------------------+
| id | name            | url                               |
+----+-----------------+-----------------------------------+
|  1 | dwnld_btn.png   | C:\shareapp\admin\dwnld_btn.png   |
+----+-----------------+-----------------------------------+

是否可以通过使用 hibernate 进行连接，一个简单的示例对我来说是一个入门。

我试过了

mysql> Select fileid,name,url from filesshare fs,filesinfo fi where fs.fileid=fi
.id;
+--------+-----------------+-----------------------------------+
| fileid | name            | url                               |
+--------+-----------------+-----------------------------------+
|      1 | dwnld_btn.png   | C:\shareapp\admin\dwnld_btn.png   |
|      1 | dwnld_btn.png   | C:\shareapp\admin\dwnld_btn.png   |
|      1 | dwnld_btn.png   | C:\shareapp\admin\dwnld_btn.png   |
|      1 | dwnld_btn.png   | C:\shareapp\admin\dwnld_btn.png   |
|      2 | dwnld_btn_1.png | C:\shareapp\admin\dwnld_btn_1.png |
|      2 | dwnld_btn_1.png | C:\shareapp\admin\dwnld_btn_1.png |
|      2 | dwnld_btn_1.png | C:\shareapp\admin\dwnld_btn_1.png |
|      2 | dwnld_btn_1.png | C:\shareapp\admin\dwnld_btn_1.png |
+--------+-----------------+-----------------------------------+

感谢和问候

Answer 1

在hibernate中你可以通过两种方式来处理它：

• 使用普通的 sql

  示例： SQLQuery query = session.createSQLQuery("select fi.* from fileshare fs, filesinfo fi where fs.fileId =fi.id and fs.userId = :uid and fs.owner = :oid"); query.setInteger("uid", userid); query.setInteger("oid", ownerid);

     /*maybe deal with transformation */
     query.setResultTransformer(Criteria.ALIAS_TO_ENTITY_MAP);)
     return  (List<Map<String,Object>>)query.list();   
  

  这里是转换细节信息的链接： http://docs.jboss.org/hibernate/core/3.3/reference/en/html/querycriteria.html#querycriteria-associations

• 使用 hql 假设你有实体映射到

  示例：

    Criteria crit =  session.createCriteria(Filesinfo.class)
    crit.setFetchMode("fs.fileshare", FetchMode.JOIN);
    crit.add( Restrictions.eq("fs.userId", userid) Restrictions.eq("fs.owner", ownerid) );
    return crit.list();
  
  all info on this method is here: http://docs.jboss.org/hibernate/orm/3.3/reference/en-US/html/queryhql.html
  
   and here is the details of teh ORM mapping via xml: http://docs.jboss.org/hibernate/core/3.3/reference/en/html/xml.html
  

Answer 2

Select id,name,url from fileshare fs,filesinfo fi where fs.id=fs.id;

Answer 3

k 伙计们这一个摸不着头脑，当然也来自 google 的帮助。

     mysql> select a.id, a.name, a.url from filesinfo a inner join filesshare b on 
a.id=b.fileid where b.userid=5 and b.owner=1;
    +----+-----------------+-----------------------------------+
    | id | name            | url                               |
    +----+-----------------+-----------------------------------+
    |  2 | dwnld_btn_1.png | C:\shareapp\admin\dwnld_btn_1.png |
    |  4 | loader3.gif     | C:\shareapp\admin\loader3.gif     |
    +----+-----------------+-----------------------------------+
    2 rows in set (0.02 sec)