我有一个User
和一个Log
类(我不能更改):
class User {
private long id;
private String name;
private Set<Log> accessLogs;
private Set<Log> actionLogs;
}
class Log {
private String what;
private Date when;
}
可能的映射如下:
<class name="com.example.User" table="users">
<id name="id" access="field">
<generator class="native" />
</id>
<property name="name" length="256" />
<set name="accessLogs" table="user_access_logs" cascade="all-delete-orphan" order-by="`when`">
<key column="user_id" />
<composite-element class="com.example.Log">
<property name="what" length="512" />
<property name="when" column="`when`" />
</composite-element>
</set>
<set name="actionLogs" table="user_action_logs" cascade="all-delete-orphan" order-by="`when`">
<key column="user_id" />
<composite-element class="com.example.Log">
<property name="what" length="512" />
<property name="when" column="`when`" />
</composite-element>
</set>
</class>
这个代码工作正常,并映射到以下数据库表:
users
+----+------+
| id | name |
+----+------+
| 1 | john |
| 2 | bill |
| 3 | nick |
+----+------+
user_access_logs
+---------+------------+---------------------+
| user_id | what | when |
+---------+------------+---------------------+
| 1 | logged in | 2010-09-21 11:25:03 |
| 1 | logged out | 2010-09-21 11:38:24 |
| 1 | logged in | 2010-09-22 10:19:39 |
| 2 | logged in | 2010-09-22 11:03:18 |
| 1 | logged out | 2010-09-22 11:48:16 |
| 2 | logged in | 2010-09-26 12:45:18 |
+---------+------------+---------------------+
user_action_logs
+---------+---------------+---------------------+
| user_id | what | when |
+---------+---------------+---------------------+
| 1 | edit profile | 2010-09-21 11:28:13 |
| 1 | post comment | 2010-09-21 11:30:40 |
| 1 | edit profile | 2010-09-21 11:31:17 |
| 1 | submit link | 2010-09-22 10:21:02 |
| 2 | submit review | 2010-09-22 11:10:22 |
| 2 | submit link | 2010-09-22 11:11:39 |
+---------+---------------+---------------------+
我的问题是,在 Hibernate 中如何将这两个集合 (accessLogs
和 actionLogs
) 映射到同一张表格,生成如下日志模式:
user_logs
+---------+---------------+---------------------+--------+
| user_id | what | when | type |
+---------+---------------+---------------------+--------+
| 1 | logged in | 2010-09-21 11:25:03 | access |
| 1 | edit profile | 2010-09-21 11:28:13 | action |
| 1 | post comment | 2010-09-21 11:30:40 | action |
| 1 | edit profile | 2010-09-21 11:31:17 | action |
| 1 | logged out | 2010-09-21 11:38:24 | access |
| 1 | logged in | 2010-09-22 10:19:39 | access |
| 1 | submit link | 2010-09-22 10:21:02 | action |
| 2 | logged in | 2010-09-22 11:03:18 | access |
| 2 | submit review | 2010-09-22 11:10:22 | action |
| 2 | submit link | 2010-09-22 11:11:39 | action |
| 1 | logged out | 2010-09-22 11:48:16 | access |
| 2 | logged in | 2010-09-26 12:45:18 | access |
+---------+---------------+---------------------+--------+
编辑: 我希望保留Java代码和Set语义不变。我正在寻找类似于鉴别器、公式或Hibernate API扩展的东西,可以在不触及Java代码的情况下解决这个问题。也许有些类似以下(虚构的Hibernate配置):
<set name="accessLogs" table="user_logs" ... formula="type='access'">
<key column="user_id" />
<composite-element class="Log">
...
</composite-element>
</set>
<set name="actionLogs" table="user_logs" ... formula="type='action'">
<key column="user_id" />
<composite-element class="Log">
...
</composite-element>
</set>
编辑2:我还没有完整的解决方案。我相信它是可以完成的,可能需要扩展一些Hibernate API。
user_id
、what
和when
字段。 - cherouvim