Question

I have and entity with two fields an id and a code as so…

@Id
@GeneratedValue(strategy = GenerationType.AUTO)
@Column(name = "id")
private Integer id;

@Basic
@Column(name = "code", nullable = false)
private String code;

What I would like is to do is, to generate the code based on the Auto-incremented id (Using Mysql as DB).

Is there a way without using a table to generate keys for the code column.
i.e

• id = 1 code is M-000-1
• id = 2 code is M-000-2 etc..

The only way I have managed to do this is using the script below. Which I am not so sure is the correct way.

getEntityManager().persist(myEntity);
getEntityManager().flush();
myEntity.setCode(myEntity.getCode()+myEntity.getId());
getEntityManager().merge(myEntity);

Thanks in advance!
Dimitri

Answer 1

Looks fine. You can perhaps move it to a @PostPersist handler.