Question

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Hibernate UnUniqueify a column in table(Solved)

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I want a field set to be non-unique on itself but to be unique in combination with the other field, I got this table with two columns(composite primary keys); id (primary key) and object_proxy_id (primary key), this is exactly what I need but hibernate sets the object_proxy_id to be unique on itself so that value cant be duplicate in the table, and I need this column to accept duplicate values. Because every user has its own object proxy and these proxy’s don’t have to be necessarily unique.

This is what I want to achieve:

|-------------------------------|
| 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                  |
|-------------------------------|

Current code:

@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...*/
}

Results in:

-- 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 !!!!
|------------------|

EDIT:
The two primary key’s in tbl_object_proxy are composite primary key’s
I have tried Xeon’s solution but it didn’t work.

Answer 1

Short answer: replace the @ElementCollection by a @ManyToMany relation with a @JoinTable like this:

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

See “2.2.5.3.2.1. Definition” in Hibernate Annotation Documentation

This results in a same side table but then without the unique constraint.
So now this is possible:

|-------------------------------|
| 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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Detailed answer and cause description:
Somehow the @ElementCollection created a collectiontable with a one to many relation of the referenced key (collection | inverse join) which adds a unique constraint to the key referencing the other side table to reflect the one to many relationship which I didn’t want. So I dropped the @ElementCollection and replaced it by a @ManyToMany relation with a @JoinTable annotation. I have also tried to declare the @ManyToMany relation in the @ElementCollection but it kept adding the Unique constraint to the referenced key.

My Settings class does now look like this:

@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...*/
}