JPA 2: multiple column usage in foreign keys

Question

I am using Hibernate as persistence provider and modelling my entities with JPA 2.

Now a question came up and i hope you can help me.

In my application you can

Answer 1

Are you sure you can't use insertable = false, updateable = false for these @JoinColumns?

As far as I understand, you can initialize gameid once by setting game property, and after that you don't need to change it since Tiles and Groups belong to the same Game.

Answer 2

You need to do this:

@ManyToOne
@JoinColumns({
    @JoinColumn(name="gameid", referencedColumnName = "gameid", insertable = false, updatable = false ),
    @JoinColumn(name="groupTag", referencedColumnName = "grouptag", insertable = false, updatable = false)
})
private Group group;

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EDIT: as mentioned in the comments, @JoinColumn is a repeatable annotation (since Java 8) that doesn't need wrapping. This simplifies the solution to:

@ManyToOne
@JoinColumn(name="gameid", referencedColumnName = "gameid", insertable = false, updatable = false ),
@JoinColumn(name="groupTag", referencedColumnName = "grouptag", insertable = false, updatable = false)
private Group group;