休眠UniqueConstraint

Question

For example I have some entity like:

@Entity
public class WorkingScheduleOverride implements Serializable {

    private static final long serialVersionUID = 1L;

    @Id
    @GeneratedValue(strategy = GenerationType.AUTO)
    private Long id;

    @Version
    private Integer version;

    @Column
    private Date validFrom;

    @Column
    private Date validThru;

    @Column
    private Date timestamp;

    @Column(unique = true)
    private Date date;

To check that the entity is unique by field date I added (unique = true) . This works fine, but only if not to use "closable" approach to entities. It is for the cases if you want keep track the history of these objects. So I'm using 'validThru' field to specify till what time the entity is valid.

So my question is: is it possible by using any custom validations/annotations to check on uniqueness ONLY VALID entities (validThru == null || validThru < new Date()) .

Incorrect data in database (two records has the same date and both are valid):

-----------------------------------------------------------------
id  |version    |timestamp  |valid_from |valid_thru |date       |
-----------------------------------------------------------------
1   |1          |2012-01-01 |2012-01-01 |null       |2013-01-01 |
-----------------------------------------------------------------
2   |1          |2012-01-01 |2012-01-01 |null       |2013-01-01 |
-----------------------------------------------------------------

Correct data in database (two records has the same date but second record is invalid):

-----------------------------------------------------------------
id  |version    |timestamp  |valid_from |valid_thru |date       |
-----------------------------------------------------------------
1   |1          |2012-01-01 |2012-01-01 |null       |2013-01-01 |
-----------------------------------------------------------------
2   |1          |2012-01-01 |2012-01-01 |2012-06-01 |2013-01-01 |
-----------------------------------------------------------------

Incorrect data in database (two records has the same date and both are valid, second record becomes invalid only 1th of January 2014):

-----------------------------------------------------------------
id  |version    |timestamp  |valid_from |valid_thru |date       |
-----------------------------------------------------------------
1   |1          |2012-01-01 |2012-01-01 |null       |2013-01-01 |
-----------------------------------------------------------------
2   |1          |2012-01-01 |2012-01-01 |2014-01-01 |2013-01-01 |
-----------------------------------------------------------------

Thanks

Answer 1

I'm not sure to understand your question but.

@PreUpdate
@PrePersist
public void checkEntity() {
    if ( validThru != null && validThru.getTime() > new Date().getTime() ) {
        throw new SomeException("Invalid entity");
    }
}

may do the job.

---

When you use unique=true the constraint is not at the code level, it is at the db level. If you want to ensure more advanced constraints, create a trigger that will reject the inserts and updates.

If a trigger can't be coded, you have to enforce your entity consistency with applicative code. Create a service with a save(entity) that will reject the bad entities with an exception.

Answer 2

Instead of date,You can use TimeStamp.and unique column constraint on verion and id.So that any of the situation Your record could unique. Another way you can use status as a column Where praticular record Valid-V and Invalid -I.you can show only valid or invalid records based on the selection