java - Hibernate 取消唯一化表中的列

Question

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Hibernate UnUniqueify a column in table(已解决)

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我希望一个字段集本身是非唯一的，但与另一个字段组合是唯一的，我得到了这个有两列(复合主键)的表； id(主键)和 object_proxy_id(主键)，这正是我所需要的，但是 hibernate 将 object_proxy_id 设置为自身唯一，以便表中的值不能重复，我需要此列来接受重复值。因为每个用户都有自己的对象代理，而这些代理不一定是唯一的。

这就是我想要实现的目标:

|-------------------------------|
| tbl_object_proxy              |
| ------------------------------|
| Id (pk)| object_proxy_id (pk) |
|-------------------------------|
| 1      | 150 --               |
| 1      | 149  |= must be able to be DUPLICATE which is not the case right now.
| 2      | 150 --               |
| 2      | 151                  |
|-------------------------------|

当前代码:

@Entity
@Table(name = "tbl_user_settings", uniqueConstraints = {@UniqueConstraint(columnNames={"user_id"})})
@Inheritance(strategy = InheritanceType.TABLE_PER_CLASS)

public class Settings implements Serializable
{
@Id
@SequenceGenerator(name="someSequence", sequenceName="SEQ_SOMENAME", allocationSize =1)
@GeneratedValue(strategy=GenerationType.SEQUENCE, generator="someSequence")
@Column(name="id")
private int setting_id;

@OneToOne
private User user;

@ManyToOne
private SomeObject someobject;

@ElementCollection
@CollectionTable(name="tbl_collection_name", joinColumns=
@JoinColumn(name="id"), uniqueConstraints = {@UniqueConstraint(columnNames={"id", "object_proxy_id"})})
@Column(name="SomeObject")
private Set<SomeObject> objectProxy;

/*...constructors and methods...*/
}

结果:

-- Table schema
|-------------------|                    
| tbl_user_settings |                        
|-------------------|                        
| id                |PK <<Unique>>                      
| user_id           |FK reference tbl_user <<Unique>>                        
| object_id         |FK reference tbl_object  
|-------------------|

|------------------|
| tbl_object_proxy |
|------------------|
| id               |PK reference tbl_user_settings 
| object_proxy_id  |PK reference tbl_object <<Unique>> BUT I DON'T WANT THIS TO BE UNIQUE ON ITSELF !!!!
|------------------|

编辑:tbl_object_proxy 中的两个主键是复合主键
我试过 Xeon 的解决方案，但没有用。

Answer 1

简答:用 @ManyToMany 关系替换 @ElementCollection 与 @JoinTable 如下:

@ManyToMany
@JoinTable(
name="tbl_settings_objecteproxy_v2",
joinColumns = @JoinColumn(name = "id"),
inverseJoinColumns = @JoinColumn( name = "objectproxy_id"))
private Set<SomeObject> objectproxy;

参见 Hibernate Annotation Documentation 中的“2.2.5.3.2.1. 定义”

这会产生相同的边表，但没有唯一约束。所以现在这是可能的:

|-------------------------------|
| tbl_object_proxy              |
| ------------------------------|
| Id (pk)| object_proxy_id (pk) |
|-------------------------------|
| 1      | 150 --               |
| 1      | 149  |= It works! The unique constraint is gone! 
| 2      | 150 --               |
| 2      | 151                  |
|-------------------------------|

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详细答案及原因描述:@ElementCollection 以某种方式创建了一个集合表，该集合表具有引用键的一对多关系(集合 | 反向连接)，它添加了一个唯一约束引用另一边表的键来反射(reflect)我不想要的一对多关系。所以我删除了 @ElementCollection 并将其替换为带有 @JoinTable 注释的 @ManyToMany 关系。我还尝试在 @ElementCollection 中声明 @ManyToMany 关系，但它一直向引用的键添加 Unique 约束。

我的设置类现在看起来像这样:

@Entity
@Table(name = "tbl_user_settings", uniqueConstraints = {@UniqueConstraint(columnNames={"user_id"})})
@Inheritance(strategy = InheritanceType.TABLE_PER_CLASS)

public class Settings
{
@Id
@SequenceGenerator(name="someSequence", sequenceName="SEQ_SOMENAME", allocationSize =1)
@GeneratedValue(strategy=GenerationType.SEQUENCE, generator="someSequence")
@Column(name="id")
private int setting_id;

@OneToOne
private User user;

@ManyToOne
private SomeObject someobject;

@ManyToMany
@JoinTable(
name="tbl_settings_objecteproxy_v2",
joinColumns = @JoinColumn(name = "id"),
inverseJoinColumns = @JoinColumn( name = "objectproxy_id"))
private Set<SomeObject> objectProxy;

/*...the rest...*/
}