Auto Increment key based on another column via JPA

Question

Is there any way to increment a key based on column rather than a row. i.e.:

ColA , ColB, ColC A , 1 , text3 B , 1 , text12 A , 2 , any text55 A , 3 , any text4 B , 2 , any text55

When ColA contains same value then ColB value is incremented. Is there any way to do it via JPA or Hibernate rather than doing query of Max ?

As this is a JPA question, posting the relevant Entities might be useful.Is @OrderColumn of any use? docs.oracle.com/javaee/6/api/javax/persistence/OrderColumn.html — Alan Hay
– Alan Hay, Commented Apr 14, 2016 at 12:39
When a record is inserted it's id should be incremented. as you can see ColB increment for ColA. — Asad Khan
– Asad Khan, Commented Apr 14, 2016 at 13:40
Then do you still think @OrderColumn will work? Is there any example? — Asad Khan
– Asad Khan, Commented Apr 15, 2016 at 5:22

Zaknafein · Accepted Answer · 2016-04-14 10:58:19Z

1

i think you need to implement logic into the when you add a new item.

You can use @PrePersist annotatiom

answered Apr 14, 2016 at 10:40

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3 Comments

This is not an aswer, should be a comment

Then don't answer because this way your answer will be deleted, and start earning reputation to be able to comment.

I appreciate his answer @haytem